drm/rockchip: vop: initialize registers directly

At present we are using init_table to initialize some
registers, but the Register init table use un-document define,
it is unreadable, and sometimes we only want to update tiny
bits, init table method is not friendly, it's diffcult to
reuse for difference chips.

To make it clean, initialize registers directly, and drops
init_table mechanism out.

Signed-off-by: Mark Yao <mark.yao@rock-chips.com>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Reviewed-by: Jeffy Chen <jeffy.chen@rock-chips.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1501049946-5877-1-git-send-email-mark.yao@rock-chips.com