rockchip: dts: tinker: Add tinker-s board support

Support tinker-s board. The board is equivalent of tinker board
except of emmc.

TODO:
- support of usb current burst when the board is powered from pc

Signed-off-by: Michael Trimarchi <michael@amarulasolutions.com>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>