IB/srpt: Post receive work requests after qp transition to INIT state

IB and iWARP specs both spell out that posting a receive work request
to a queue pair in the RESET state is an invalid operation and required
to fail.  Postpone posting receive work requests until after the
transition to the INIT state.

Fixes: commit dea26209 ("IB/srpt: Change default behavior from using SRQ to using RC")
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>