f2fs: fix a deadlock during init_acl procedure

The deadlock is found through the following scenario.

sys_mkdir()
 -> f2fs_add_link()
  -> __f2fs_add_link()
   -> init_inode_metadata()
     : lock_page(inode);
    -> f2fs_init_acl()
     -> f2fs_set_acl()
      -> f2fs_setxattr(..., NULL)
       : This NULL page incurs a deadlock at update_inode_page().

So, likewise f2fs_init_security(), this patch adds a parameter to transfer the
locked inode page to f2fs_setxattr().

Found by Linux File System Verification project (linuxtesting.org).

Reported-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>