Revert "ARM: dts: rockchip: drop grf reference from rk3036 hdmi"

Revert "ARM: dts: rockchip: drop grf reference from rk3036 hdmi"

This reverts commit 1580ccb6ed9dc76b8ff3e2d8912e8215c8b0fa6d.

The HSYNC/VSYNC polarity of rk3036 HDMI are controlled by GRF.
Without the polarity configuration in GRF, it can be observed from
the HDMI protocol analyzer that the H/V front/back timing output
by RK3036 HDMI are currently not in line with the specifications.

Signed-off-by: Andy Yan <andy.yan@rock-chips.com>
Tested-by: Heiko Stuebner <heiko@sntech.de> #rk3036-kylin
Link: https://lore.kernel.org/r/20250422070455.432666-7-andyshrk@163.com
Signed-off-by: Heiko Stuebner <heiko@sntech.de>