[Headers][X86] Fix incorrect macro definitions for non-constexpr (#153060)

While working on PR #152910, I discovered some incorrectly defined
`__DEFAULT_FN_ATTRS*_CONSTEXPR` macros for non-constexpr contexts.

Author: markbhasawut

clang/lib/Headers/avx512fintrin.h

@@ -180,9 +180,9 @@ typedef enum
 #define __DEFAULT_FN_ATTRS512_CONSTEXPR __DEFAULT_FN_ATTRS512 constexpr
 #define __DEFAULT_FN_ATTRS128_CONSTEXPR __DEFAULT_FN_ATTRS128 constexpr
 #else
-#define __DEFAULT_FN_ATTRS_CONSTEXPR __DEFAULT_FN_ATTRS128
+#define __DEFAULT_FN_ATTRS_CONSTEXPR __DEFAULT_FN_ATTRS
 #define __DEFAULT_FN_ATTRS512_CONSTEXPR __DEFAULT_FN_ATTRS512
-#define __DEFAULT_FN_ATTRS128_CONSTEXPR __DEFAULT_FN_ATTRS
+#define __DEFAULT_FN_ATTRS128_CONSTEXPR __DEFAULT_FN_ATTRS128
 #endif
 
 /* Create vectors with repeated elements */

clang/lib/Headers/avxintrin.h

@@ -70,8 +70,8 @@ typedef __bf16 __m256bh __attribute__((__vector_size__(32), __aligned__(32)));
 #define __DEFAULT_FN_ATTRS_CONSTEXPR __DEFAULT_FN_ATTRS constexpr
 #define __DEFAULT_FN_ATTRS128_CONSTEXPR __DEFAULT_FN_ATTRS128 constexpr
 #else
-#define __DEFAULT_FN_ATTRS_CONSTEXPR __DEFAULT_FN_ATTRS128
-#define __DEFAULT_FN_ATTRS128_CONSTEXPR __DEFAULT_FN_ATTRS
+#define __DEFAULT_FN_ATTRS_CONSTEXPR __DEFAULT_FN_ATTRS
+#define __DEFAULT_FN_ATTRS128_CONSTEXPR __DEFAULT_FN_ATTRS128
 #endif
 
 /* Arithmetic */