[AARCH64] Remove Load/Store register (unscaled immediate) alias.

[AARCH64] Remove Load/Store register (unscaled immediate) alias.

opcodes/ChangeLog:

2015-03-10  Renlin Li  <renlin.li@arm.com>

	* aarch64-tbl.h (aarch64_opcode_table): Remove strub, ldurb, ldursb,
         stur, ldur, sturh, ldurh, ldursh, ldursw, prfum F_HAS_ALIAS flag and
         related alias.
	* aarch64-asm-2.c: Regenerate.
	* aarch64-dis-2.c: Likewise.
	* aarch64-opc-2.c: Likewise.

gas/testsuite/ChangeLog:

2015-03-10  Renlin Li  <renlin.li@arm.com>

	* gas/aarch64/ldst-reg-uns-imm.d: Adjust expected output.
	* gas/aarch64/ldst-reg-unscaled-imm.d: Likewise.
	* gas/aarch64/reloc-insn.d: Likewise.