sim: move register headers into sim/ namespace [PR sim/29869]

These headers define the register numbers for each port to implement
the sim_fetch_register & sim_store_register interfaces.  While gdb
uses these, the APIs are part of the sim, not gdb.  Move the headers
out of the gdb/ include namespace and into sim/ instead.

include/sim/sim-rx.h

@@ -0,0 +1,56 @@
+/* sim-rx.h --- interface between RX simulator and GDB.
+
+   Copyright (C) 2008-2022 Free Software Foundation, Inc.
+
+   Contributed by Red Hat.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#if !defined (SIM_RX_H)
+#define SIM_RX_H
+
+enum sim_rx_regnum
+  {
+    sim_rx_r0_regnum,
+    sim_rx_r1_regnum,
+    sim_rx_r2_regnum,
+    sim_rx_r3_regnum,
+    sim_rx_r4_regnum,
+    sim_rx_r5_regnum,
+    sim_rx_r6_regnum,
+    sim_rx_r7_regnum,
+    sim_rx_r8_regnum,
+    sim_rx_r9_regnum,
+    sim_rx_r10_regnum,
+    sim_rx_r11_regnum,
+    sim_rx_r12_regnum,
+    sim_rx_r13_regnum,
+    sim_rx_r14_regnum,
+    sim_rx_r15_regnum,
+    sim_rx_usp_regnum,
+    sim_rx_isp_regnum,
+    sim_rx_ps_regnum,
+    sim_rx_pc_regnum,
+    sim_rx_intb_regnum,
+    sim_rx_bpsw_regnum,
+    sim_rx_bpc_regnum,
+    sim_rx_fintv_regnum,
+    sim_rx_fpsw_regnum,
+    sim_rx_acc_regnum,
+    sim_rx_num_regs
+  };
+
+#endif /* SIM_RX_H */