qlge: Fix bug in MTU setting process.

Since an FCoE function shares a port with this NIC function, the
jumbo settings must always be in place.  This patch causes the
hardware to be set up for jumbo if it is not already done.

Signed-off-by: Ron Mercer <ron.mercer@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>