[BINUTILS, AARCH64, 3/8] Add Pointer Arithmetic instructions in Memory Tagging Extension

[BINUTILS, AARCH64, 3/8] Add Pointer Arithmetic instructions in Memory Tagging Extension

This patch is part of the patch series to add support for ARMv8.5-A
Memory Tagging Extensions which is an optional extension to
ARMv8.5-A and is enabled using the +memtag command line option.

This patch add support to the Pointer Arithmetic instructions from
MTE. These are the following instructions added in this patch:
- SUBP <Xd>, <Xn|SP>, <Xm|SP>
- SUBPS <Xd>, <Xn|SP>, <Xm|SP>
- CMPP <Xn|SP>, <Xm|SP>
where CMPP is an alias to SUBPS XZR, <Xn|SP>, <Xm|SP>

where
<Xd> : Is the 64-bit destination GPR.
<Xn|SP> : Is the 64-bit first source GPR or Stack pointer.
<Xm|SP> : Is the 64-bit second source GPR or Stack pointer.

*** opcodes/ChangeLog ***

2018-11-12  Sudakshina Das  <sudi.das@arm.com>

	* aarch64-tbl.h (aarch64_opcode_table): Add subp, subps and cmpp.
	* aarch64-asm-2.c: Regenerated.
	* aarch64-dis-2.c: Regenerated.
	* aarch64-opc-2.c: Regenerated.

*** gas/ChangeLog ***

2018-11-12  Sudakshina Das  <sudi.das@arm.com>

	* testsuite/gas/aarch64/armv8_5-a-memtag.s: Add tests for subp,
	subps and cmpp.
	* testsuite/gas/aarch64/armv8_5-a-memtag.d: Likewise.
	* testsuite/gas/aarch64/illegal-memtag.s: Likewise.
	* testsuite/gas/aarch64/illegal-memtag.l: Likewise.