lpfc: fix boot from san failure

lpfc: fix boot from san failure

Fixed boot from san failure when SLI4 FC device presented on the same PCI bus

http://marc.info/?l=linux-scsi&m=135170912526110

The request_firmware interface can induce delays while looking
for firmware files, even if no fw file is present. In some situations
the delays exceeded scan_wait timeouts, resulting in situations in which
the boot device had not been discovered in time.  Boot Device does not
need to be on a lpfc device.

Change request_firmware use to be module paramater driven. Default is to
not attempt firmware download on boot. Add sysfs parameter to invoke
firmware update.

Signed-off-by: James Smart <james.smart@emulex.com>