Fix test whitespace

Author: chrisjbris

llvm/test/CodeGen/AMDGPU/ptradd-sdag-optimizations.ll

@@ -307,4 +307,4 @@ define ptr @fold_mul24_into_mad(ptr %base, i64 %a, i64 %b) {
   %mul = mul i64 %a_masked, %b_masked
   %gep = getelementptr inbounds i8, ptr %base, i64 %mul
   ret ptr %gep
-}
+}