drm/vc4: hdmi: Move pixel doubling from Pixelvalve to HDMI block

With the change to 2 pixels/clock, the pixel doubling in the PV
results in doubling each pair of pixels, ie ABABCDCD instead of
AABBCCDD.

Move the pixel doubling to the HDMI block, however this means
that DBLCLK modes now fall foul of requiring even values for
all the horizontal timing parameters.
As both 480i and 576i fail this, attempt to fix up DBLCLK modes
that have odd timings values.

Fixes: 83239891

 ("drm/vc4: hdmi: Support the BCM2711 HDMI controllers")
Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Link: https://lore.kernel.org/r/20220613144800.326124-34-maxime@cerno.tech
Signed-off-by: Maxime Ripard <maxime@cerno.tech>