cifs: SMB1 split: Don't return smb_hdr from cifs_{,small_}buf_get()

cifs: SMB1 split: Don't return smb_hdr from cifs_{,small_}buf_get()

Return void* rather than struct smb_hdr* from from cifs_buf_get() and
cifs_small_buf_get() as SMB2/3 shouldn't be accessing smb_hdr.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Steve French <sfrench@samba.org>
cc: Paulo Alcantara <pc@manguebit.org>
cc: Enzo Matsumiya <ematsumiya@suse.de>
cc: linux-cifs@vger.kernel.org
cc: linux-fsdevel@vger.kernel.org
cc: linux-kernel@vger.kernel.org
Acked-by: Enzo Matsumiya <ematsumiya@suse.de>
Signed-off-by: Steve French <stfrench@microsoft.com>