builtins-mergew-mergeow.c: Update dg-requires.

[testsuite]

2018-02-07  Will Schmidt  <will_schmidt@vnet.ibm.com>

	* gcc.target/powerpc/builtins-mergew-mergeow.c:  Update dg-requires.

From-SVN: r257469

gcc/testsuite/ChangeLog

+2018-02-07  Will Schmidt  <will_schmidt@vnet.ibm.com>
+
+	* gcc.target/powerpc/builtins-mergew-mergeow.c:  Update dg-requires.
+
 2018-02-07  Jakub Jelinek  <jakub@redhat.com>
 
 	PR c++/84082

gcc/testsuite/gcc.target/powerpc/builtins-mergew-mergow.c

 /* { dg-do run } */
-/* { dg-require-effective-target vsx_hw } */
-/* { dg-options "-maltivec -mvsx" } */
+/* { dg-require-effective-target p8vector_hw } */
+/* { dg-options "-mpower8-vector" } */
 
 #include <altivec.h> // vector
 #include <stdlib.h>