drm/panel: sitronix-st7789v: add panel orientation support

Determine the orientation of the display based on the device tree and
propagate it.

Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Reviewed-by: Sebastian Reichel <sre@kernel.org>
Signed-off-by: Michael Riesch <michael.riesch@wolfvision.net>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230718-feature-st7789v-v3-2-157d68fb63e2@wolfvision.net