[SCSI] qla2xxx: Add full firmware(-request) hotplug support for all ISPs.

Transition driver to exclusively use the request_firmware()
interfaces to retrieve firmware-blobs from user-space.  This
will be the default behaviour going forward until the
embedded firmware-binary images are removed from the
upstream kernel.

Upon request, the driver caches the firmware image until the
driver is unloaded.

NOTE: The option is present to allow the user to continue to
use the firmware-loader modules, but, should be considered
deprecated.

Signed-off-by: Andrew Vasquez <andrew.vasquez@qlogic.com>
Rejections fixed up and
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>