qlcnic: release device resources during interface down

Previously we were allocating device resources during probe and
release them during remove.
Now alloc during interface up and release in interface down.
This helps in device performance, as it doesn't need to keep
track of inactive resources.

Signed-off-by: Amit Kumar Salecha <amit.salecha@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>