add missing transmutes to ppc tests

Author: gnzlbg

coresimd/powerpc/altivec.rs

@@ -528,7 +528,7 @@ mod tests {
                 let a: $longtype = ::mem::transmute($shorttype::new($($a),+));
                 let b = ::mem::transmute($shorttype::new($($b),+));
                 let c = ::mem::transmute(u8x16::new($($c),+));
-                let d = $shorttype::new($($d),+);
+                let d = ::mem::transmute($shorttype::new($($d),+));
 
                 assert_eq!(d, ::mem::transmute(vec_perm(a, b, c)));
             }