ARM: dts: Augment panel setting for Versatile

This adds the actual VGA DAC bridge that is used in the
Versatile AB, and sets the mode to 640x480 VGA.

The "clcd" clock was incorrectly named, the proper name
(from bindings) is "clcdclk". So far drivers survived
by just getting the first clock, but future drivers will
use named clocks.

We add the panel connector to the
"arm,versatile-tft-panel" as well, the signals actually
fork on the board, reaching both the VGA DAC and the
display connector.

Cc: Mali DP Maintainers <malidp@foss.arm.com>
Reviewed-by: Liviu Dudau <liviu.dudau@arm.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>