netxen: fix thermal check and shutdown

Check temperature for all PCI functions, that can allow
graceful shutdown of all interfaces on the overheated card.

Old code was only monitoring temperature for function 0 only.

Signed-off-by: Dhananjay Phadke <dhananjay@netxen.com>
Signed-off-by: David S. Miller <davem@davemloft.net>