drm/rockchip: vop: introduce VOP_REG_MASK

Some new vop register support mask, bit[16-31] is mask,
bit[0-15] is value, the mask is correspond to the value.

Signed-off-by: Mark Yao <mark.yao@rock-chips.com>
[seanpaul masked 'v' per tfiga's review comments]
Reviewed-by: Mark Yao <mark.yao@rock-chips.com>
Signed-off-by: Sean Paul <seanpaul@chromium.org>