[PATCH] skge: handle out of memory on MTU size changes

Changing the MTU size causes the receiver to have to reallocate buffers.
If this allocation fails, then we need to return an error, and take
the device offline. It can then be brought back up or reconfigured
for a smaller MTU.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>