qlcnic: Disable INT-x interrupt for 83xx on driver unload

o Set HW mask for 8300 Series adapter, in INT-x mode, to
  stop generating interrupt during driver unload.

Signed-off-by: Himanshu Madhani <himanshu.madhani@qlogic.com>
Signed-off-by: Shahed Shaikh <shahed.shaikh@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>