Add fallback compatibility string.
This is in keeping with the fallback scheme being adopted wherever
appropriate for drivers for Renesas SoCs.
Signed-off-by: NSimon Horman <horms+renesas@verge.net.au>
Acked-by: NRob Herring <robh@kernel.org>
Signed-off-by: NMauro Carvalho Chehab <mchehab@osg.samsung.com>