qla2xxx: Enable Extended Logins support

This patch enables Extended Logins support in Qlogic ISP.
To enable extended login with Qlogic ISP24XX/25XX/26XX,
set module parameter ql2xexlogins to any non-zero number.
This will alow ISP firmware to store port database structure
information of remote login sessions to host memory provided
by driver. ISP firmware supports upto 16k total logins.

Signed-off-by: Himanshu Madhani <himanshu.madhani@qlogic.com>
Signed-off-by: Giridhar Malavali <giridhar.malavali@qlogic.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>