1. wpa_supplicatn use extra SHA default
2. mbedtls use extra SHA default
3. bootloader use extra SHA default
4. user code can use extra SHA default
Above all, using unified module is easy to maintenance code and save rom or ram.
1. support save cal data in nvs;
2. support use phy partition to store init data;
In old SDK, we use (max_sec - 3) as init data sector, and (max_sec - 4) as cal data sector. This is changed in IDF style SDK, and these 2 sectors can be used for other perpose.
