Issue:
System crash while target discovery for ISP40XX

Root cause:
Function qla4xxx_init_rings() is not called for ISP40XX

Fix:
Call function qla4xxx_init_rings() for ISP40XX from
qla4xxx_start_firmware().
Signed-off-by: Vikas Chaudhary <vikas.chaudhary@qlogic.com>
Reviewed-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: Christoph Hellwig <hch@lst.de>