Add a compatible string for the LCD controller found in the JZ4770 SoC.

v2: No change
Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Acked-by: Rob Herring <robh@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20191210144142.33143-1-paul@crapouillou.net
# *** extracted tags ***
Acked-by: Sam Ravnborg <sam@ravnborg.org>