iw_cxgb4: dump detailed driver-specific QP information

Provide a cxgb4-specific function to fill in qp state details.
This allows dumping important c4iw_qp state useful for debugging.

Included in the dump are the t4_sq, t4_rq structs, plus a dump
of the t4_swsqe and t4swrqe descriptors for the first and last
pending entries.

Signed-off-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>