boards: nucleo_wb5rg: Add a c2h device
boards: nucleo_wb5rg: Add a c2h device

Add a chosen c2h to enable use of transparent mode over uart.

Additionally add cts/rts pins and enable hw flow control to lpuart1
for H4 protocol support.

Signed-off-by: Erwan Gouriou <de4d967452b83bb0e37525652734e7d9163b6a4c@linaro.org>

zephyrproject-rtos/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,galak/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,galak/zephyr