[SCSI] qla2xxx: Add char device to increase driver use count

The driver should not be unloaded if any application is using it.
To disallow driver unload, driver use count must be incremented.
Application uses this char device as handle and increases driver
use count to avoid possible driver unload.

Signed-off-by: Giridhar Malavali <giridhar.malavali@qlogic.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>