iw_cxgb4: enforce qp/cq id requirements

Currently the iw_cxgb4 implementation requires the qp and cq qid densities
to match as well as the qp and cq id ranges.  So fail a device open if
the device configuration doesn't meet the requirements.

The reason for these restictions has to do with the fact that IQ qid X
has a UGTS register in the same bar2 page as EQ qid X.  Thus both qids
need to be allocated to the same user process for security reasons.
The logic that does this (the qpid allocator in iw_cxgb4/resource.c)
handles this but requires the above restrictions.

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