RISC-V: Add support for RISC-V Profiles 20/22.

RISC-V: Add support for RISC-V Profiles 20/22.

This patch introduces support for RISC-V Profiles RV20 and RV22 [1],
enabling developers to utilize these profiles through the -march option.

[1] https://github.com/riscv/riscv-profiles/releases/tag/v1.0

bfd/ChangeLog:

	* elfxx-riscv.c (struct riscv_profiles): New struct.
	(riscv_parse_extensions): New argument.
	(riscv_find_profiles): New checking function.
	(riscv_parse_subset): Add Profiles handler.

gas/ChangeLog:

	* NEWS: Add RISC-V Profiles.
	* doc/as.texi: Update -march input type.
	* doc/c-riscv.texi: Ditto.
	* testsuite/gas/riscv/option-arch-fail.l: Modify hint info.
	* testsuite/gas/riscv/attribute-17.d: New test.
	* testsuite/gas/riscv/attribute-18.d: New test.
	* testsuite/gas/riscv/march-fail-rvi20u64v.d: New test.
	* testsuite/gas/riscv/march-fail-rvi20u64v.l: New test.