drm/vc4: hdmi: Do the VID_CTL configuration at once

The VID_CTL setup is done in several places in the driver even though it's
not really required. Let's simplify it a bit to do the configuration in one
go.

Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Tested-by: Chanwoo Choi <cw00.choi@samsung.com>
Tested-by: Hoegeun Kwon <hoegeun.kwon@samsung.com>
Tested-by: Stefan Wahren <stefan.wahren@i2se.com>
Reviewed-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Link: https://patchwork.freedesktop.org/patch/msgid/08e7ebb605a560fcc149b69b4af52753a7870b2f.1599120059.git-series.maxime@cerno.tech