testsuite: Fix up sse3-addsubps.c

testsuite: Fix up sse3-addsubps.c

The testcase uses sizeof (vals) / sizeof (vals) as the number of vals to
handle (though, handles 8 vals at a time).  That is an obvious typo,
all similar testcases use sizeof (vals) / sizeof (vals[0]) properly.

2024-08-10  Jakub Jelinek  <jakub@redhat.com>

	* gcc.target/powerpc/sse3-addsubps.c (TEST): Divide by
	sizeof (vals[0]) rather than sizeof (vals).