PowerPC D-form prefixed loads and stores

PowerPC D-form prefixed loads and stores

opcodes/
	* ppc-opc.c (insert_d34, extract_d34, insert_nsi34, extract_nsi34),
	(insert_pcrel, extract_pcrel, extract_pcrel0): New functions.
	(extract_esync, extract_raq, extract_tbr, extract_sxl): Comment.
	(powerpc_operands <D34, SI34, NSI34, PRA0, PRAQ, PCREL, PCREL0,
	XTOP>): Define and add entries.
	(P8LS, PMLS, P_D_MASK, P_DRAPCREL_MASK): Define.
	(prefix_opcodes): Add pli, paddi, pla, psubi, plwz, plbz, pstw,
	pstb, plhz, plha, psth, plfs, plfd, pstfs, pstfd, plq, plxsd,
	plxssp, pld, plwa, pstxsd, pstxssp, pstxv, pstd, and pstq.
gas/
	* config/tc-ppc.c (ppc_insert_operand): Only sign extend fields that
	are 32-bits or smaller.
	* messages.c (as_internal_value_out_of_range): Do not truncate
	variables and use BFD_VMA_FMT to print them.
	* testsuite/gas/ppc/prefix-pcrel.s,
	* testsuite/gas/ppc/prefix-pcrel.d: New test.
	* testsuite/gas/ppc/ppc.exp: Run it.