rpi: add Compute Module 3+

Add Raspberry Pi Compute Module 3+ to list of models, the revision code
is 0x10 according to the list on raspberrypi.org.

v2: Use the same dtb name as CM3 as CM3+ is a drop in replacement
    for CM3.

Signed-off-by: Jonathan Gray <jsg@jsg.id.au>
Reviewed-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Matthias Brugger <mbrugger@suse.com>