cxgbe/iw_cxgbe: Tidy up a couple of CTRs in c4iw_create_listen.

backlog is an int and not a string. While here, fix an adjacent CTR
that was spread over two lines even though it fits in one.

Sponsored by: Chelsio Communications

(cherry picked from commit 3f250bb6f05b57890215398767bbb8aa00c888f3)