aarch64: Treat operand "SME list of ZA tiles" as immediate (PR 31561)

aarch64: Treat operand "SME list of ZA tiles" as immediate (PR 31561)

The AArch64 instruction table (aarch64-tbl.h) defines the operand
"SME list of ZA tiles" (SME_list_of_64bit_tiles) as immediate. During
assembly it is correctly encoded as immediate value (imm.value) in
parse_operands. During disassembly it is first correctly decoded as
immediate value (imm.value) in aarch64_ext_imm called by
aarch64_extract_operand, but then erroneously treated as register
number (reg.regno) in aarch64_print_operand.

This resolves the assembler test case "SME extension (ZERO)" to
erroneously fail on s390. On AArch64 - being little-endian - the struct
aarch64_opnd_info union fields reg.regno and imm.value share their
least-significant bits. On s390 - being big-endian - they do not.

opcodes/
	PR binutils/31561
	* aarch64-opc.c: Treat operand "SME list of ZA tiles" as
	immediate.

Bug: https://sourceware.org/PR31561
Signed-off-by: Jens Remus <jremus@linux.ibm.com>
Acked-by: Nick Clifton <nickc@redhat.com>