IB/rdmavt: Move SRQ data structure into rdmavt

Patch moves the srq data structure into rdmavt in preparation for
removal from qib and hfi1 which will follow in subsequent patches.

Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Harish Chegondi <harish.chegondi@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>