Power10 Reduced precision outer product operations

include/
	* opcode/ppc.h (PPC_OPERAND_ACC): Define.  Renumber following
	PPC_OPERAND defines.
opcodes/
	* ppc-opc.c (insert_xa6a, extract_xa6a, insert_xb6a, extract_xb6a):
	New functions.
	(powerpc_operands): Define ACC, PMSK8, PMSK4, PMSK2, XMSK, YMSK,
	YMSK2, XA6a, XA6ap, XB6a entries.
	(PMMIRR, P_X_MASK, P_XX1_MASK, P_GER_MASK): Define
	(P_GER2_MASK, P_GER4_MASK, P_GER8_MASK, P_GER64_MASK): Define.
	(PPCVSX4): Define.
	(powerpc_opcodes): Add xxmfacc, xxmtacc, xxsetaccz,
	xvi8ger4pp, xvi8ger4, xvf16ger2pp, xvf16ger2, xvf32gerpp, xvf32ger,
	xvi4ger8pp, xvi4ger8, xvi16ger2spp, xvi16ger2s, xvbf16ger2pp,
	xvbf16ger2, xvf64gerpp, xvf64ger, xvi16ger2, xvf16ger2np,
	xvf32gernp, xvi8ger4spp, xvi16ger2pp, xvbf16ger2np, xvf64gernp,
	xvf16ger2pn, xvf32gerpn, xvbf16ger2pn, xvf64gerpn, xvf16ger2nn,
	xvf32gernn, xvbf16ger2nn, xvf64gernn, xvcvbf16sp, xvcvspbf16.
	(prefix_opcodes): Add pmxvi8ger4pp, pmxvi8ger4, pmxvf16ger2pp,
	pmxvf16ger2, pmxvf32gerpp, pmxvf32ger, pmxvi4ger8pp, pmxvi4ger8,
	pmxvi16ger2spp, pmxvi16ger2s, pmxvbf16ger2pp, pmxvbf16ger2,
	pmxvf64gerpp, pmxvf64ger, pmxvi16ger2, pmxvf16ger2np, pmxvf32gernp,
	pmxvi8ger4spp, pmxvi16ger2pp, pmxvbf16ger2np, pmxvf64gernp,
	pmxvf16ger2pn, pmxvf32gerpn, pmxvbf16ger2pn, pmxvf64gerpn,
	pmxvf16ger2nn, pmxvf32gernn, pmxvbf16ger2nn, pmxvf64gernn.
gas/
	* config/tc-ppc.c (pre_defined_registers): Add accumulators.
	(md_assemble): Check acc specified in correct operand.
	* testsuite/gas/ppc/outerprod.d,
	* testsuite/gas/ppc/outerprod.s,
	* testsuite/gas/ppc/vsx4.d,
	* testsuite/gas/ppc/vsx4.s: New tests.
	* testsuite/gas/ppc/ppc.exp: Run them.