[SCSI] qla4xxx: Free Device Database (DDB) reserved by FW

Firmware reserves DDBs if there are entries in the FLASH.
So there are no free DDBs left when a iSCSI login is initiated
by user space tool like iscsiadm.
Since now login is not controlled by firmware, LLD need to free
up the DDBs after firmware init. This will ensure free DDBs are
available for iSCSI logins using iscsiadm.

JIRA Key: UPSISCSI-151

Signed-off-by: Lalit Chandivade <lalit.chandivade@qlogic.com>
Signed-off-by: Vikas Chaudhary <vikas.chaudhary@qlogic.com>
Reviewed-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>