[SCSI] qla2xxx: Clear complete initialization control block.

Use proper init_cb_size member which takes into account
MID/non-MID init-cb structure sizes.

Signed-off-by: Andrew Vasquez <andrew.vasquez@qlogic.com>
Signed-off-by: Madhuranath Iyengar <Madhu.Iyengar@qlogic.com>
Signed-off-by: James Bottomley <jbottomley@parallels.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>