IB/qib: Fix QLE734X link cycling

The SERDES was using the incorrect Frequency Loop Bandwidth setting
causing the link to cycle through the Physical link negotiation state
machine.  Fixing the Frequency Loop Bandwidth setting in the SERDES
helps the link come up faster and more reliably.

Signed-off-by: Mitko Haralanov <mitko.haralanov@intel.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>