[PATCH,rs6000] Testsuite fixup pr96139 tests

Hi,
  As reported, the recently added pr96139 tests will fail on older targets
  because the tests are missing the appropriate -mvsx or -maltivec options.
  This adds the options and clarifies the dg-require statements.

  The pr96139-c.c test needs -maltivec to work, but does not actually use
  vectors, so does not require -mvsx like the others.

  Sniff-regtested OK when specifying older targets on a power7 host.
  --target_board=unix/'{-mcpu=power4,-mcpu=power5,-mcpu=power6,-mcpu=power7,
  -mcpu=power8,-mcpu=power9}''{-m64,-m32}'"


gcc/testsuite/ChangeLog:
	* gcc.target/powerpc/pr96139-a.c: Specify -mvsx option and update the
	dg-require stanza to match.
	* gcc.target/powerpc/pr96139-b.c: Same.
	* gcc.target/powerpc/pr96139-c.c: Specify -maltivec option and update
	the dg-require stanza to match.

gcc/testsuite/gcc.target/powerpc/pr96139-a.c

@@ -1,7 +1,7 @@
 /* { dg-do compile } */
-/* { dg-options "-O2 -Wall -m32" } */
+/* { dg-options "-O2 -Wall -m32 -mvsx" } */
 /* { dg-require-effective-target ilp32 } */
-/* { dg-require-effective-target powerpc_altivec_ok } */
+/* { dg-require-effective-target powerpc_vsx_ok } */
 
 #include <stdio.h>
 #include <altivec.h>

gcc/testsuite/gcc.target/powerpc/pr96139-b.c

@@ -1,7 +1,7 @@
 /* { dg-do compile } */
-/* { dg-options "-O2 -Wall -m64" } */
+/* { dg-options "-O2 -Wall -m64 -mvsx" } */
 /* { dg-require-effective-target lp64 } */
-/* { dg-require-effective-target powerpc_altivec_ok } */
+/* { dg-require-effective-target powerpc_vsx_ok } */
 
 #include <stdio.h>
 #include <altivec.h>

gcc/testsuite/gcc.target/powerpc/pr96139-c.c

@@ -1,5 +1,5 @@
 /* { dg-do run } */
-/* { dg-options "-O2 -Wall" } */
+/* { dg-options "-O2 -Wall -maltivec" } */
 /* { dg-require-effective-target powerpc_altivec_ok } */
 
 /*