[Morello] Make DC, IC capability aware in C64.

[Morello] Make DC, IC capability aware in C64.

gas/ChangeLog:

2020-10-20  Siddhesh Poyarekar  <siddesh.poyarekar@arm.com>

	* config/tc-aarch64.c (process_omitted_operand,
	parse_operands): Add Cat_SYS.
	* testsuite/gas/aarch64/morello_ldst-c64.d: Add tests.
	* testsuite/gas/aarch64/morello_ldst.d: Likewise.
	* testsuite/gas/aarch64/morello_ldst.s: Likewise.

include/ChangeLog:

2020-10-20  Siddhesh Poyarekar  <siddesh.poyarekar@arm.com>

	* opcode/aarch64.h (aarch64_opnd): New operand Cat_SYS.

opcodes/ChangeLog:

2020-10-20  Siddhesh Poyarekar  <siddesh.poyarekar@arm.com>

	* aarch64-opc.c (operand_general_constraint_met_p): Expect
	capability registers for cache operations in C64.
	(aarch64_print_operand): Print register arguments for cache
	instructions correctly.
	* aarch64-tbl.h (aarch64_opcode_table): New instructions.
	(AARCH64_OPERANDS): New operands.
	* aarch64-asm-2.c: Regenerate.
	* aarch64-dis-2.c: Regenerate.
	* aarch64-opc-2.c: Regenerate.