IB/ipoib: Suppress the retry related completion errors

IPoIB doesn't support transport/rnr retry schemes as per
RFC so those errors are expected. No need to flood the
log files with them.

Tested-by: Michael Nowak <michael.nowak@oracle.com>
Tested-by: Rafael Alejandro Peralez <rafael.peralez@oracle.com>
Tested-by: Liwen Huang <liwen.huang@oracle.com>
Tested-by: Hong Liu <hong.x.liu@oracle.com>
Reviewed-by: Mukesh Kacker <mukesh.kacker@oracle.com>
Reported-by: Rajiv Raja <rajiv.raja@oracle.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>
Signed-off-by: Yuval Shaia <yuval.shaia@oracle.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>