staging/rdma/hfi1: Add aeth name syndrome decode

Add aeth name syndrome decode to enhance debugging.

The IBTA RC ACK contains an ACK extended transport header.

Part of that header is the syndrome field that qualifies the RC ACK as an
ACK, NAK, or RNR NAK.

Without the patch here is the syndrome decode:
aeth syn 0x00

Here is the decode with the fix:
aeth syn 0x00 ACK

Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Dean Luick <dean.luick@intel.com>
Signed-off-by: Jubin John <jubin.john@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>