[PATCH, rs6000] correct implementation of _mm_add_pi32

[Steven Munroe]

A small thinko in the implementation of _mm_add_pi32 that only shows
when compiling for power9.

./gcc/ChangeLog:

2017-11-15  Steven Munroe  <munro...@gcc.gnu.org>

        * config/rs6000/mmintrin.h (_mm_add_pi32[_ARCH_PWR]): Correct
        parameter list for vec_splats.

Index: gcc/config/rs6000/mmintrin.h
===================================================================
--- gcc/config/rs6000/mmintrin.h        (revision 254714)
+++ gcc/config/rs6000/mmintrin.h        (working copy)
@@ -463,8 +463,8 @@ _mm_add_pi32 (__m64 __m1, __m64 __m2)
 #if _ARCH_PWR9
   __vector signed int a, b, c;
 
-  a = (__vector signed int)vec_splats (__m1, __m1);
-  b = (__vector signed int)vec_splats (__m2, __m2);
+  a = (__vector signed int)vec_splats (__m1);
+  b = (__vector signed int)vec_splats (__m2);
   c = vec_add (a, b);
   return (__builtin_unpack_vector_int128 ((__vector __int128_t)c, 0));
 #else