Add support for handling the HS/VS sync signals polarity in the bridge
driver, otherwise e.g. DSIM bridge feeds the TC358762 inverted polarity
sync signals and the image is shifted to the left, up, and wobbly.

Signed-off-by: Marek Vasut <marex@denx.de>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Robert Foss <rfoss@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230615201902.566182-5-marex@denx.de