[SCSI] qla2xxx: Re-sync module parameter descriptions with the code

Fix module parameter descriptions mentioning default values that no longer
match the code.

Signed-off-by: Steven J. Magnani <steve@digidescorp.com>
Acked-by: Chad Dupuis <chad.dupuis@qlogic.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>