cifs: fix missing unlock in cifs_file_copychunk_range()

cifs: fix missing unlock in cifs_file_copychunk_range()

xfstests generic/013 and generic/476 reported WARNING as follows:

  WARNING: lock held when returning to user space!
  6.1.0-rc5+ #4 Not tainted
  ------------------------------------------------
  fsstress/504233 is leaving the kernel with locks still held!
  2 locks held by fsstress/504233:
   #0: ffff888054c38850 (&sb->s_type->i_mutex_key#21){+.+.}-{3:3}, at:
                        lock_two_nondirectories+0xcf/0xf0
   #1: ffff8880b8fec750 (&sb->s_type->i_mutex_key#21/4){+.+.}-{3:3}, at:
                        lock_two_nondirectories+0xb7/0xf0

This will lead to deadlock and hungtask.

Fix this by releasing locks when failed to write out on a file range in
cifs_file_copychunk_range().

Fixes: 3e3761f1ec7d ("smb3: use filemap_write_and_wait_range instead of filemap_write_and_wait")
Cc: stable@vger.kernel.org # 6.0
Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: ChenXiaoSong <chenxiaosong2@huawei.com>
Signed-off-by: Steve French <stfrench@microsoft.com>