arm64: dts: rockchip: Add BT support on px30-engicam

arm64: dts: rockchip: Add BT support on px30-engicam

Engicam PX30 carrier boards like EDIMM2.2 and C.TOUCH2.0 have
an onboard Sterling-LWD Wifi/BT chip based on BCM43430 connected
on the UART bus.

UART bus on the design routed via USB to UART CP20x bridge. This
bridge powered from 3V3 regualtor gpio.

This patch adds BT enablement nodes for these respective boards.

Signed-off-by: Michael Trimarchi <michael@amarulasolutions.com>
Signed-off-by: Suniel Mahesh <sunil@amarulasolutions.com>
Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
Link: https://lore.kernel.org/r/20201109181017.206834-7-jagan@amarulasolutions.com
Signed-off-by: Heiko Stuebner <heiko@sntech.de>