[SCSI] qla2xxx: Defer explicit interrupt-polling processing to init-time scenarios.

As the intermixing may cause issues where HCCR bits could be
cleared inappropriately during MSI/MSI-X interrupt handling.

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