RISC-V: The vtype immediate with more than the defined 8 bits are preserved.

According the rvv spec,
https://github.com/riscv/riscv-v-spec/blob/master/vtype-format.adoc

The bits of vtype immediate from 8 to (xlen - 1) should be reserved.
Therefore, we should also dump the vtype immediate as numbers, when
they are set over 8-bits.  I think this is a bug that we used to support
vediv extension and use the bit 8 and 9 of vtype, but forgot to update
the behavior when removing the vediv.

Consider the testcases,

vsetvli  a0, a1,  0x700    # the reserved bit 10, 9 and 8 are used.
vsetvli  a0, a1,  0x400    # the reserved bit 10 is used.
vsetvli  a0, a1,  0x300    # the reserved bit 9 and 8 are used.
vsetvli  a0, a1,  0x100    # the reserved bit 8 is used.
vsetivli a0, 0xb, 0x300    # the reserved bit 9 and 8 are used.
vsetivli a0, 0xb, 0x100    # the reserved bit 8 is used.

The original objdump shows the following result,

0000000000000000 <.text>:
   0:   7005f557                vsetvli a0,a1,1792
   4:   4005f557                vsetvli a0,a1,1024
   8:   3005f557                vsetvli a0,a1,e8,m1,tu,mu
   c:   1005f557                vsetvli a0,a1,e8,m1,tu,mu
  10:   f005f557                vsetivli        a0,11,e8,m1,tu,mu
  14:   d005f557                vsetivli        a0,11,e8,m1,tu,mu

But in fact the correct result should be,

0000000000000000 <.text>:
   0:   7005f557                vsetvli a0,a1,1792
   4:   4005f557                vsetvli a0,a1,1024
   8:   3005f557                vsetvli a0,a1,768
   c:   1005f557                vsetvli a0,a1,256
  10:   f005f557                vsetivli        a0,11,768
  14:   d005f557                vsetivli        a0,11,256

gas/
	* testsuite/gas/riscv/vector-insns.d: Added testcases to
	test the reserved bit 8 to (xlen-1) of vtype.
	* testsuite/gas/riscv/vector-insns.s: Likewise.
include/
	* opcode/riscv.h: Removed OP_MASK_VTYPE_RES and OP_SH_VTYPE_RES,
	since they are different for operand Vc and Vb.
opcodes/
	* riscv-dis.c (print_insn_args): Updated imm_vtype_res to
	extract the reserved immediate of vtype correctly.

gas/testsuite/gas/riscv/vector-insns.d

@@ -24,6 +24,12 @@ Disassembly of section .text:
 [ 	]+[0-9a-f]+:[ 	]+c4a5f557[ 	]+vsetivli[ 	]+a0,11,e16,m4,ta,mu
 [ 	]+[0-9a-f]+:[ 	]+c165f557[ 	]+vsetivli[ 	]+a0,11,e32,mf4,tu,mu
 [ 	]+[0-9a-f]+:[ 	]+c9d5f557[ 	]+vsetivli[ 	]+a0,11,e64,mf8,tu,ma
+[ 	]+[0-9a-f]+:[ 	]+7005f557[ 	]+vsetvli[ 	]+a0,a1,1792
+[ 	]+[0-9a-f]+:[ 	]+4005f557[ 	]+vsetvli[ 	]+a0,a1,1024
+[ 	]+[0-9a-f]+:[ 	]+3005f557[ 	]+vsetvli[ 	]+a0,a1,768
+[ 	]+[0-9a-f]+:[ 	]+1005f557[ 	]+vsetvli[ 	]+a0,a1,256
+[ 	]+[0-9a-f]+:[ 	]+f005f557[ 	]+vsetivli[ 	]+a0,11,768
+[ 	]+[0-9a-f]+:[ 	]+d005f557[ 	]+vsetivli[ 	]+a0,11,256
 [ 	]+[0-9a-f]+:[ 	]+02b50207[ 	]+vlm.v[ 	]+v4,\(a0\)
 [ 	]+[0-9a-f]+:[ 	]+02b50207[ 	]+vlm.v[ 	]+v4,\(a0\)
 [ 	]+[0-9a-f]+:[ 	]+02b50207[ 	]+vlm.v[ 	]+v4,\(a0\)

gas/testsuite/gas/riscv/vector-insns.s

@@ -16,6 +16,13 @@
 	vsetivli a0, 0xb, e32, mf4, mu
 	vsetivli a0, 0xb, e64, mf8, tu, ma
 
+	vsetvli  a0, a1,  0x700
+	vsetvli  a0, a1,  0x400
+	vsetvli  a0, a1,  0x300
+	vsetvli  a0, a1,  0x100
+	vsetivli a0, 0xb, 0x300
+	vsetivli a0, 0xb, 0x100
+
 	vlm.v v4, (a0)
 	vlm.v v4, 0(a0)
 	vle1.v v4, (a0)		# Alias of vlm.v

include/opcode/riscv.h

@@ -306,8 +306,6 @@ static const char * const riscv_pred_succ[16] =
 #define OP_SH_VTA		6
 #define OP_MASK_VMA		0x1
 #define OP_SH_VMA		7
-#define OP_MASK_VTYPE_RES	0x1
-#define OP_SH_VTYPE_RES		10
 #define OP_MASK_VWD		0x1
 #define OP_SH_VWD		26
 

opcodes/riscv-dis.c

@@ -328,7 +328,7 @@ print_insn_args (const char *oparg, insn_t l, bfd_vma pc, disassemble_info *info
 		unsigned int imm_vsew = EXTRACT_OPERAND (VSEW, imm);
 		unsigned int imm_vta = EXTRACT_OPERAND (VTA, imm);
 		unsigned int imm_vma = EXTRACT_OPERAND (VMA, imm);
-		unsigned int imm_vtype_res = EXTRACT_OPERAND (VTYPE_RES, imm);
+		unsigned int imm_vtype_res = (imm >> 8);
 
 		if (imm_vsew < ARRAY_SIZE (riscv_vsew)
 		    && imm_vlmul < ARRAY_SIZE (riscv_vlmul)