tegra: lcd: Merge tegra124-lcd.c into display.c

There isn't a lot of benefit of have two separate files. With driver model
the code needs to be in the same driver, so it's better to have it in the
same file.

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Anatolij Gustschin <agust@denx.de>
Signed-off-by: Tom Warren <twarren@nvidia.com>