kfdtest: Fix String NULL Check

MCPU const char * always returns true, so check the value instead.

Before: if (!MCPU) {
After: if (!*MCPU) {

Signed-off-by: Ori Messinger <Ori.Messinger@amd.com>
Change-Id: I414e091ca764095937311648c534351d6abf30e6


[ROCm/ROCR-Runtime commit: 5f117f7608]

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

@@ -249,7 +249,7 @@ int Assembler::RunAssembleBuf(const char* const AssemblySource, char* OutBuf,
  */
 int Assembler::RunAssemble(const char* const AssemblySource) {
     // Ensure target ASIC has been set
-    if (!MCPU) {
+    if (!*MCPU) {
         outs() << "ASM Error: target asic is uninitialized\n";
         return -1;
     }