Added #include "arm_neon.h" to ARM gemm ukernel.

Details:
- Inserted #include "arm_neon.h" into gemm ukernel source file for
  arm/neon. Thanks to Jean-Michel Hautbois for suggesting this fix.

kernels/arm/neon/3/bli_gemm_opt_4x4.c

@@ -33,6 +33,7 @@
 */
 
 #include "blis.h"
+#include "arm_neon.h"
 
 void bli_sgemm_opt_4x4(
                         dim_t              k,