[SCSI] qla4xxx: Re-register IRQ handler while retrying initialize of adapter

Problem:
If initialization of adapter fails for some reason, then the interrupt handlers
are released. The interrupt handlers are not registered again when initialization
of adapter is retried.

Solution:
Re-register the interrupt handler when adapter initialization is retried.

Signed-off-by: Poornima Vonti <poornima.vonti@qlogic.com>
Signed-off-by: Vikas Chaudhary <vikas.chaudhary@qlogic.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>