Fix endless loop

Fix a while loop that can cause forever loop when cpuid instruction
doesn't work properly.

Change-Id: Iefa49d23b40c994eb4369621974a7d3c4067e47a
Signed-off-by: Amber Lin <Amber.Lin@amd.com>


[ROCm/ROCR-Runtime commit: 5815d9de9b]

projects/rocr-runtime/src/topology.c

@@ -354,7 +354,8 @@ static int cpuid_find_num_cache_leaves(uint32_t op)
 	do {
 		++idx;
 		cpuid_count(op, idx, &eax.full, &ebx.full, &ecx, &edx);
-	} while (eax.split.type != CACHE_TYPE_NULL);
+		/* Modern systems have cache levels up to 3. */
+	} while (eax.split.type != CACHE_TYPE_NULL && idx < 4);
 	return idx;
 }