rs6000: Adjust mov optabs for opaque modes [PR103353]

rs6000: Adjust mov optabs for opaque modes [PR103353]

As PR103353 shows, we may want to continue to expand built-in
function __builtin_vsx_lxvp, even if we have already emitted
error messages about some missing required conditions.  As
shown in that PR, without one explicit mov optab on OOmode
provided, it would call emit_move_insn recursively.

So this patch is to allow the mov pattern to be generated during
expanding phase if compiler has already seen errors.

	PR target/103353

gcc/ChangeLog:

	* config/rs6000/mma.md (define_expand movpoi): Move TARGET_MMA condition
	check to preparation statements and add handlings for !TARGET_MMA.
	(define_expand movpxi): Likewise.

gcc/testsuite/ChangeLog:

	* gcc.target/powerpc/pr103353.c: New test.

(cherry picked from commit 9367e3a65f874dffc8f8a3b6760e77fd9ed67117)