scsi: fnic: Impose upper limit on max. # of CQs processed per intr

Impose an upper limit on the max number of CQ entries (corresponding to the
copy wq) processed in an interrupt.  Use module parameter to set the limit.

Signed-off-by: Satish Kharat <satishkh@cisco.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>