RDMA/cxgb4: remove unnecessary NULL check in __c4iw_poll_cq_one()

RDMA/cxgb4: remove unnecessary NULL check in __c4iw_poll_cq_one()

If 'qhp' is NULL then 'wq' is also NULL:

    struct t4_wq *wq = qhp ? &qhp->wq : NULL;
    ...
    ret = poll_cq(wq, ...);
    if (ret)
        goto out;

poll_cq(wq, ...) always returns a non-zero status if 'wq' is NULL,
either on a t4_next_cqe() error or on a 'wq == NULL' check.

Therefore, checking 'qhp' again after poll_cq() is redundant.

BTW, there're also 'qhp' dereference cases below poll_cq() without
any checks (c4iw_invalidate_mr(qhp->rhp,...)).

Detected using the static analysis tool - Svace.

Fixes: 4ab39e2f98f2 ("RDMA/cxgb4: Make c4iw_poll_cq_one() easier to analyze")
Signed-off-by: Alexey Kodanev <aleksei.kodanev@bell-sw.com>
Link: https://lore.kernel.org/r/20221215123030.155378-1-aleksei.kodanev@bell-sw.com
Signed-off-by: Leon Romanovsky <leon@kernel.org>