[SCSI] qla2xxx: list cursors are not null

This is just a cleanup.

The unneeded NULL check annoys static checkers because we already
derefenced it and the we check it and then (if it's not the _safe()
version) we dereference it again without checking.  And the static
checker is all, "Wah?  Is it null or not?"

Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Madhuranath Iyengar <Madhu.Iyengar@qlogic.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>