IB/hfi1: Fix handling of FECN marked multicast packet

The code for handling a marked UD packet unconditionally returns the
dlid in the header of the FECN marked packet.  This is not correct
for multicast packets where the DLID is in the multicast range.

The subsequent attempt to send the CNP with the multicast lid will
cause the chip to halt the ack send context because the source
lid doesn't match the chip programming.   The send context will
be halted and flush any other pending packets in the pio ring causing
the CNP to not be sent.

A part of investigating the fix, it was determined that the 16B work
broke the FECN routine badly with inconsistent use of 16 bit and 32 bits
types for lids and pkeys.  Since the port's source lid was correctly 32
bits the type mixmatches need to be dealt with at the same time as
fixing the CNP header issue.

Fix these issues by:
- Using the ports lid for as the SLID for responding to FECN marked UD
  packets
- Insure pkey is always 16 bit in this and subordinate routines
- Insure lids are 32 bits in this and subordinate routines

Cc: <stable@vger.kernel.org> # 4.14.x
Fixes: 88733e3b ("IB/hfi1: Add 16B UD support")
Reviewed-by: Don Hiatt <don.hiatt@intel.com>
Reviewed-by: Michael J. Ruhl <michael.j.ruhl@intel.com>
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>