irdma(4): fix potential memory leak on qhash cqp operation

It was found that in some circumstances when launching
non-waiting create qhash cqp operation the refcount on
the cqp_request may be not properly decremented leading to a memory
leak.

Signed-off-by: Bartosz Sobczak <bartosz.sobczak@intel.com>

Reviewed by: anzhu_netapp.com
Tested by: mateusz.moga_intel.com
Approved by: kbowling (mentor)
MFC after: 1 week
Sponsored by: Intel Corporation
Differential Revision: https://reviews.freebsd.org/D53732