linux.inc: CONFIG_AEABI is required for chromeos kernel

Signed-off-by: Graeme Gregory <graeme.gregory@linaro.org>
chromebook-snow: update machine features and modules

This machine has wifi and bluetooth, pull in the modules and also the
asix usb net model as that is pretty common for debugging in google
world. Pull in marvell firmware too.

Signed-off-by: Graeme Gregory <graeme@xora.org.uk>
firmware-sd8797: recipe for marvel firmware for chromebook-snow

Signed-off-by: Graeme Gregory <graeme.gregory@linaro.org>