Added support for __mul24 and __umul24

include/hip/hcc_detail/hip_runtime.h

@@ -430,6 +430,9 @@ __device__ unsigned int atomicInc(unsigned int* address,
 __device__ unsigned int atomicDec(unsigned int* address,
                        unsigned int val);
 
+//__mul24 __umul24
+__device__  int __mul24(int arg1, int arg2);
+__device__  unsigned int __umul24(unsigned int arg1, unsigned int arg2);
 
 // integer intrinsic function __poc __clz __ffs __brev
 __device__ unsigned int __popc( unsigned int input);