f2fs: constify super_operations

super_operations are not supposed to change at runtime.
"struct super_block" working with super_operations provided
by <linux/fs.h> work with const super_operations. So mark
the non-const structs as const

Signed-off-by: Arvind Yadav <[e-mail]>
Reviewed-by: Chao Yu <[e-mail]>
Signed-off-by: Jaegeuk Kim <[e-mail]>

fs/f2fs/super.c

···
 }
 #endif
 
-static struct super_operations f2fs_sops = {
+static const struct super_operations f2fs_sops = {
 	.alloc_inode	= f2fs_alloc_inode,
 	.drop_inode	= f2fs_drop_inode,
 	.destroy_inode	= f2fs_destroy_inode,