v64_intrinsics.h: fix v64_align signature

add correct type for 'c' parameter

BUG=aomedia:500

Change-Id: I4ea2334405d8d7ea436bc373dd1c812666f98067
diff --git a/aom_dsp/simd/v64_intrinsics.h b/aom_dsp/simd/v64_intrinsics.h
index ee2b683..5c0042d 100644
--- a/aom_dsp/simd/v64_intrinsics.h
+++ b/aom_dsp/simd/v64_intrinsics.h
@@ -60,7 +60,9 @@
   c_v64_store_aligned(p, a);
 }
 
-SIMD_INLINE v64 v64_align(v64 a, v64 b, c) { return c_v64_align(a, b, c); }
+SIMD_INLINE v64 v64_align(v64 a, v64 b, unsigned int c) {
+  return c_v64_align(a, b, c);
+}
 
 SIMD_INLINE v64 v64_zero() { return c_v64_zero(); }
 SIMD_INLINE v64 v64_dup_8(uint8_t x) { return c_v64_dup_8(x); }