arm64/mpam: mon: add WARN_ON for debug free_pmg

hulk inclusion
category: feature
bugzilla: 5510
CVE: NA
Signed-off-by: NXie XiuQi <xiexiuqi@huawei.com>
Reviewed-by: NHanjun Guo <guohanjun@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

arch/arm64/kernel/mpam_mon.c

@@ -64,6 +64,8 @@ int alloc_pmg(void)
 
 void free_pmg(u32 pmg)
 {
+	WARN_ON(!pmg);
+
 	pmg_free_map |= 1 << pmg;
 }