drm/imx/ipuv3: ipuv3-plane: reuse local variable height in atomic_update

drm/imx/ipuv3: ipuv3-plane: reuse local variable height in atomic_update

Use the already existing local variable height = drm_rect_height() >> 16
to replace other occurrences of the same value.

Suggested-by: Lucas Stach <l.stach@pengutronix.de>
Reviewed-by: Lucas Stach <l.stach@pengutronix.de>
Link: https://lore.kernel.org/r/20221220094430.3469811-1-p.zabel@pengutronix.de
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20221220094430.3469811-1-p.zabel@pengutronix.de