If changing ring parameters is unable to allocate memory, we need
to return an error and take the device down.

Fixes-bug: http://bugzilla.kernel.org/show_bug.cgi?id=5715Signed-off-by: NStephen Hemminger <shemminger@osdl.org>
Signed-off-by: NJeff Garzik <jgarzik@pobox.com>