mm,kexec: use common help functions to free reserved pages

Use common help functions to free reserved pages.
Signed-off-by: NJiang Liu <jiang.liu@huawei.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Reviewed-by: NZhang Yanfei <zhangyanfei@cn.fujitsu.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

kernel/kexec.c

@@ -1118,12 +1118,8 @@ void __weak crash_free_reserved_phys_range(unsigned long begin,
 {
 	unsigned long addr;
 
-	for (addr = begin; addr < end; addr += PAGE_SIZE) {
-		ClearPageReserved(pfn_to_page(addr >> PAGE_SHIFT));
-		init_page_count(pfn_to_page(addr >> PAGE_SHIFT));
-		free_page((unsigned long)__va(addr));
-		totalram_pages++;
-	}
+	for (addr = begin; addr < end; addr += PAGE_SIZE)
+		free_reserved_page(pfn_to_page(addr >> PAGE_SHIFT));
 }
 
 int crash_shrink_memory(unsigned long new_size)