kfdtest: Use GetSystemTickCountInMicroSec() as much as possible

GetSystemTickCountInMicroSec() wraps the function gettimeofday().

Change-Id: I7b767a6efdd1db491fc8113313945b578ac69382
Signed-off-by: Yong Zhao <Yong.Zhao@amd.com>


[ROCm/ROCR-Runtime commit: 174484aac3]

projects/rocr-runtime/tests/kfdtest/src/LinuxOSWrapper.cpp

@@ -39,7 +39,6 @@
 #include <string.h>
 #include <sys/mman.h>
 #include <sys/ioctl.h>
-#include <sys/time.h>
 
 static int protection_flags[8] = {PROT_NONE, PROT_READ, PROT_WRITE, PROT_READ | PROT_WRITE,
                                   PROT_EXEC, PROT_EXEC | PROT_READ, PROT_EXEC | PROT_WRITE,
@@ -80,12 +79,6 @@ bool MultiProcessTest(const char *testToRun, int numOfProcesses, int runsPerProc
     return false;
 }
 
-HSAuint64 GetSystemTickCountInMicroSec() {
-    struct timeval t;
-    gettimeofday(&t, 0);
-    return t.tv_sec * 1000000ULL + t.tv_usec;
-}
-
 bool SuspendAndWakeUp() {
     printf("Please press any key after the system suspends....\n");