wsl/hsakmt: Modify num_subdirs parameter to resolve the warning

Signed-off-by: lyndonli <Lyndon.Li@amd.com>
Reviewed-by: Flora Cui <flora.cui@amd.com>
Part-of: <http://10.67.69.192/wsl/libhsakmt/-/merge_requests/32>

topology.cpp

@@ -117,7 +117,7 @@ static void free_properties(node_props_t *props, int size) {
  *		Use blank string, "", to count all.
  *	Return - number of sub-directories
  */
-static int num_subdirs(char *dirpath, char *prefix) {
+static int num_subdirs(char *dirpath, const char *prefix) {
   int count = 0;
   DIR *dirp;
   struct dirent *dir;