RDMA/cxgb3: Fix uninitialized variable warning in iwch_post_send()

RDMA/cxgb3: Fix uninitialized variable warning in iwch_post_send()

    drivers/infiniband/hw/cxgb3/iwch_qp.c: In function 'iwch_post_send':
    drivers/infiniband/hw/cxgb3/iwch_qp.c:232: warning: 't3_wr_flit_cnt' may be used uninitialized in this function

This is what akpm describes as "the dopey
gcc-doesn't-know-that-foo(&var)-writes-to-var problem."

Signed-off-by: Roland Dreier <rolandd@cisco.com>
Acked-by: Steve Wise <swise@opengridcomputing.com>