There is no counter for dmawait in AIP, which hampers debugging
performance issues.

Add the counter increment when the txq is queued.

Fixes: d99dc602 ("IB/hfi1: Add functions to transmit datagram ipoib packets")
Link: https://lore.kernel.org/r/20210715160440.142451.8278.stgit@awfm-01.cornelisnetworks.comSigned-off-by: Mike Marciniszyn <mike.marciniszyn@cornelisnetworks.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>