It's a hardware bug, all window's overlay channel reset
value is same, hardware overlay would be die.

so we must initial difference id for each overlay channel.

The Channel register is supported on all vop will full design.
Following is the details for this register
VOP_WIN0_CTRL2
  bit[7:4] win_rid_win0_cbr
       axi read id of win0 cbr channel
  bit[3:0] win_rid_win0_yrgb
       axi read id of win0 yrgb channel
Signed-off-by: Mark Yao <mark.yao@rock-chips.com>
Reviewed-by: Jeffy Chen <jeffy.chen@rock-chips.com>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Link: https://patchwork.freedesktop.org/patch/msgid/1501049980-6239-1-git-send-email-mark.yao@rock-chips.com