ARM: multi_v7_defconfig: enable HDMI output for Renesas RCar

Actviate HDMI output of the RCar DU (and LVDS while we are here).
Enable the HDMI encoder chip found on Lager/Koelsch boards.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>