mm: init: Fix build waring for ascend enable features

hulk inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I66EW4
CVE: NA

----------------------------------------------------

When enable Ascend enable CONFIG_ASCEND_FEATURES, and enable
CONFIG_ASCEND_CHARGE_MIGRATE_HUGEPAGES, and build kernel image,
it will have build warning as follows:

arch/arm64/mm/init.c:736:2: warning: ISO C90 fobids mixed
declarations and code [-Wdeclaration-atfer-statement]
  736 | extern int enable_charge_mighp;
Signed-off-by: NZhang Jian <zhangjian210@huawei.com>
Reviewed-by: Nchenweilong <chenweilong@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

arch/arm64/mm/init.c

@@ -727,14 +727,20 @@ void dump_mem_limit(void)
 	}
 }
 
+#ifdef CONFIG_ASCEND_CHARGE_MIGRATE_HUGEPAGES
+extern int enable_charge_mighp;
+#endif
+
+#ifdef CONFIG_ARM64_PSEUDO_NMI
+extern bool enable_pseudo_nmi;
+#endif
+
 void ascend_enable_all_features(void)
 {
 	if (IS_ENABLED(CONFIG_ASCEND_DVPP_MMAP))
 		enable_mmap_dvpp = 1;
 
 #ifdef CONFIG_ASCEND_CHARGE_MIGRATE_HUGEPAGES
-	extern int enable_charge_mighp;
-
 	enable_charge_mighp = 1;
 #endif
 
@@ -743,8 +749,6 @@ void ascend_enable_all_features(void)
 #endif
 
 #ifdef CONFIG_ARM64_PSEUDO_NMI
-	extern bool enable_pseudo_nmi;
-
 	enable_pseudo_nmi = true;
 #endif