[PATCH v2] RISC-V: Support more rigorous check for CSR, and update them to spec 1.12.

[Nelson Chu]

Dear binutils,

I update the serious of patches for the CSR checking since the recent GDB
changes.  Please see the details as follows:

* [PATCH v2 1/4] RISC-V: Update the CSR to privilege spec 1.12.
Upadte the testsuite/gas/riscv/csr-dw-regnums since the CSR are updated.

* [PATCH v2 2/4] RISC-V: Support the ISA-dependent CSR checking.
Upadte the binutils/dwarf.c since the DECLARE_CSR is changed.

* [PATCH v2 3/4] RISC-V: Support the read-only CSR checking.
Same as the previous one.

* [PATCH v2 4/4] RISC-V: Disable the CSR checking by default.
Same as the previous one.


Thanks and Regards
Nelson