rs6000: Fix invalid address passed to __builtin_mma_disassemble_acc [PR104923]

rs6000: Fix invalid address passed to __builtin_mma_disassemble_acc [PR104923]

The mma_disassemble_output_operand predicate is too lenient on the types
of addresses it will accept, leading to combine creating invalid address
that eventually lead to ICEs in LRA.  The solution is to restrict the
addresses to indirect, indexed or those valid for quad memory accesses.

2022-03-15  Peter Bergner  <bergner@linux.ibm.com>

gcc/
	PR target/104923
	* config/rs6000/predicates.md (mma_disassemble_output_operand): Restrict
	acceptable MEM addresses.

gcc/testsuite/
	PR target/104923
	* gcc.target/powerpc/pr104923.c: New test.