RISC-V: Add support for the Zvksed ISA extension

RISC-V: Add support for the Zvksed ISA extension

Zvksed is part of the vector crypto extensions.

This extension adds the following instructions:
- vsm4k.vi
- vsm4r.[vv,vs]

bfd/ChangeLog:

	* elfxx-riscv.c (riscv_multi_subset_supports): Add instruction
	class support for Zvksed.
	(riscv_multi_subset_supports_ext): Likewise.

gas/ChangeLog:

	* testsuite/gas/riscv/zvksed.d: New test.
	* testsuite/gas/riscv/zvksed.s: New test.

include/ChangeLog:

	* opcode/riscv-opc.h (MATCH_VSM4K_VI): New.
	(MASK_VSM4K_VI): New.
	(MATCH_VSM4R_VS): New.
	(MASK_VSM4R_VS): New.
	(MATCH_VSM4R_VV): New.
	(MASK_VSM4R_VV): New.
	(DECLARE_INSN): New.
	* opcode/riscv.h (enum riscv_insn_class): Add instruction class
	support for Zvksed.

opcodes/ChangeLog:

	* riscv-opc.c: Add Zvksed instructions.

Signed-off-by: Nathan Huckleberry <nhuck@google.com>
Signed-off-by: Christoph Müllner <christoph.muellner@vrull.eu>