scsi_transport_srp: Fix two kernel-doc warnings

This patch fixes the following two kernel-doc warnings:

    Warning(drivers/scsi/scsi_transport_srp.c:819): No description found for parameter 'rport'
    Warning(include/scsi/scsi_transport_srp.h:75): Excess struct/union/enum/typedef member 'deleted' description in 'srp_rport'

Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Reported-by: Masanari Iida <standby24x7@gmail.com>
Acked-by: Sebastian Riemer <sebastian.riemer@profitbricks.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>