PowerPC: Switch to dense math names for all MMA operations.

PowerPC: Switch to dense math names for all MMA operations.

This patch changes the assembler instruction names for MMA instructions from
the original name used in power10 to the new name when used with the dense math
system.  I.e. xvf64gerpp becomes dmxvf64gerpp.  The assembler will emit the
same bits for either spelling.

For the non-prefixed MMA instructions, we add a 'dm' prefix in front of the
instruction.  However, the prefixed instructions have a 'pm' prefix, and we add
the 'dm' prefix afterwards.  To prevent having two sets of parallel int
attributes, we remove the "pm" prefix from the instruction string in the
attributes, and add it later, both in the insn name and in the output template.

2024-03-13   Michael Meissner  <meissner@linux.ibm.com>

gcc/

	* config/rs6000/mma.md (vvi4i4i8): Change the instruction to not have a
	"pm" prefix.
	(avvi4i4i8): Likewise.
	(vvi4i4i2): Likewise.
	(avvi4i4i2): Likewise.
	(vvi4i4): Likewise.
	(avvi4i4): Likewise.
	(pvi4i2): Likewise.
	(apvi4i2): Likewise.
	(vvi4i4i4): Likewise.
	(avvi4i4i4): Likewise.
	(mma_xxsetaccz): Add support for running on DMF systems, generating the
	dense math instruction and using the dense math accumulators.
	(mma_<vv>): Likewise.
	(mma_<pv>): Likewise.
	(mma_<avv>): Likewise.
	(mma_<apv>): Likewise.
	(mma_pm<vvi4i4i8>): Add support for running on DMF systems, generating
	the dense math instruction and using the dense math accumulators.
	Rename the insn with a 'pm' prefix and add either 'pm' or 'pmdm'
	prefixes based on whether we have the original MMA specification or if
	we have dense math support.
	(mma_pm<avvi4i4i8>): Likewise.
	(mma_pm<vvi4i4i2>): Likewise.
	(mma_pm<avvi4i4i2>): Likewise.
	(mma_pm<vvi4i4>): Likewise.
	(mma_pm<avvi4i4): Likewise.
	(mma_pm<pvi4i2>): Likewise.
	(mma_pm<apvi4i2): Likewise.
	(mma_pm<vvi4i4i4>): Likewise.
	(mma_pm<avvi4i4i4>): Likewise.