linux-imx

[cifs] fix null pointer check

Dan Carpenter pointed out an inconsistent null pointer check
in smb2_hdr_assemble that was pointed out by static checker.

Signed-off-by: Steve French <smfrench@gmail.com>
Reviewed-by: Sachin Prabhu <sprabhu@redhat.com>
CC: Dan Carpenter <dan.carpenter@oracle.com>w