dt-bindings: serial: snps-dw-apb-uart: Add RV1106 compatible

Add the compatible for the UARTs of the Rockchip RV1106, which are
compatible with the Synopsys DesignWare APB UART.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Heiko Stuebner <heiko@sntech.de>
Link: https://patch.msgid.link/20260714132035.v2.1.c1d92213393f49330ec14d0c670a802181b4fcbf@changeid
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>