arm64: kernel: compiling issue, need 'EXPORT_SYMBOL(clear_page)'

Need 'EXPORT_SYMBOL(clear_page)' if building with allmodconfig.

The related errors:
  ERROR: "clear_page" [fs/ocfs2/dlm/ocfs2_dlm.ko] undefined!
  ERROR: "clear_page" [fs/ntfs/ntfs.ko] undefined!
  ERROR: "clear_page" [fs/gfs2/gfs2.ko] undefined!
  ERROR: "clear_page" [fs/fuse/fuse.ko] undefined!
  ERROR: "clear_page" [fs/ext3/ext3.ko] undefined!
  ERROR: "clear_page" [fs/ext2/ext2.ko] undefined!
  ERROR: "clear_page" [fs/exofs/libore.ko] undefined!
  ERROR: "clear_page" [fs/exofs/exofs.ko] undefined!
  ERROR: "clear_page" [drivers/block/brd.ko] undefined!
Signed-off-by: Chen Gang <gang.chen@asianux.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

arch/arm64/kernel/arm64ksyms.c

@@ -34,6 +34,7 @@ EXPORT_SYMBOL(__strnlen_user);
 EXPORT_SYMBOL(__strncpy_from_user);
 
 EXPORT_SYMBOL(copy_page);
+EXPORT_SYMBOL(clear_page);
 
 EXPORT_SYMBOL(__copy_from_user);
 EXPORT_SYMBOL(__copy_to_user);