[PATCH] S2io: Support for runtime MTU change

Hi,
Patch below supports MTU change on-the-fly(without bringing interface
down)

Signed-off-by: Ravinandan Arakali <ravinandan.arakali@neterion.com>
Signed-off-by: Raghavendra Koushik <raghavendra.koushik@neterion.com>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>