[SCSI] qla2xxx: Pull-down scsi-host-addition to follow board initialization.

Return to previous held-logic of calling scsi_add_host() only
after the board has been completely initialized.  Also return
pci_*() error-codes during probe failure paths.

This also corrects an issue where only lun 0 is being scanned for
a given port.

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