DM: Fix potential buffer overflow and uninitialized variable

- @'rpmb_check_frame()', avoid buffer overflow access
    when calling 'memcmp()'

Signed-off-by: Yonghua Huang <yonghua.huang@intel.com>

devicemodel/core/hugetlb.c

@@ -506,7 +506,7 @@ static bool release_larger_freepage(int level_limit)
  */
 static bool hugetlb_reserve_pages(void)
 {
-	int left_gap, pg_size;
+	int left_gap = 0, pg_size;
 	int level;
 
 	printf("to reserve more free pages:\n");