Make the mode an integer constant expression in cmp_mask

[uidops]

I ran into a problem when I was compiling with Clang + SSE4.2
This code is invalid in clang compiler

const int mode = SIDD_UWORD_OPS | SIDD_CMP_EQUAL_EACH | SIDD_BIT_MASK;
return _mm_cmpistrm(a, b, mode);

Because _mm_cmpistrm takes mode as an integer constant expression, not a const qualified int.
For instance assume this code:

#include <smmintrin.h>

#define SIDD_UWORD_OPS _SIDD_UWORD_OPS
#define SIDD_CMP_EQUAL_EACH _SIDD_CMP_EQUAL_EACH
#define SIDD_BIT_MASK _SIDD_BIT_MASK

static inline __m128i cmp_mask(__m128i a, __m128i b) {
    const int mode = SIDD_UWORD_OPS | SIDD_CMP_EQUAL_EACH | SIDD_BIT_MASK;
    return _mm_cmpistrm(a, b, mode);
}

int main(void) {
    return 0;
}

$ clang -msse4.2 a.c -o a
a.c:11:9: error: argument to '__builtin_ia32_pcmpistrm128' must be a constant integer
        return _mm_cmpistrm(a, b, mode);
               ^~~~~~~~~~~~~~~~~~~~~~~~
/usr/lib/llvm/14/bin/../../../../lib/clang/14.0.6/include/smmintrin.h:1629:13: note: expanded from macro '_mm_cmpistrm'
  ((__m128i)__builtin_ia32_pcmpistrm128((__v16qi)(__m128i)(A), \
            ^
1 error generated.

I think other compilers like GCC have no problem if we use

return _mm_cmpistrm(a, b, SIDD_UWORD_OPS | SIDD_CMP_EQUAL_EACH | SIDD_BIT_MASK);