Do not include x86intrin.h if unavailable
This fixes compilations on arm platforms.
The call to the function itself was protected, and used clib_xxhash instead.
Only the header protection was missing.
#define CLIB_CUCKOO_OPTIMIZE_UNROLL 1
#define CLIB_CUCKOO_OPTIMIZE_USE_COUNT_LIMITS_SEARCH 1
+#if __SSE4_2__ && !defined (__i386__)
#include <x86intrin.h>
+#endif
/** 8 octet key, 8 octet key value pair */
typedef struct
