hipDispatchLatency: reduce iterations to 5120

Change-Id: I94ae4993ff5058cf15f9487a5a528fc24c1ad5fa

samples/1_Utils/hipDispatchLatency/hipDispatchLatency.cpp

@@ -30,7 +30,7 @@ if(status != hipSuccess){ \
 
 #define LEN 1024*1024
 #define SIZE LEN * sizeof(float)
-#define ITER 10000
+#define ITER 5120
 
 __global__ void One(hipLaunchParm lp, float* Ad){
 }