boards: st: nucleo_wba55cg: add 'zephyr,bt-c2h-uart'

Include 'zephyr,bt-c2h-uart' in 'chosen' node to make it possible to use
HCI raw mode over UART. This was tested on real board with 'hci_uart'
sample, with Linux machine as a host (kernel 6.8, BlueZ 5.75).

(cherry picked from commit 36d8583)

Original-Signed-off-by: Piotr Dymacz <pepe2k@gmail.com>
GitOrigin-RevId: 36d8583
Change-Id: I2f09cda9e4d80a7e2e25a33c505948501aa8963a
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/zephyr/+/5534927
Reviewed-by: Yuval Peress <peress@google.com>
Commit-Queue: Yuval Peress <peress@google.com>
Tested-by: ChromeOS Prod (Robot) <chromeos-ci-prod@chromeos-bot.iam.gserviceaccount.com>
Tested-by: Yuval Peress <peress@google.com>

boards/st/nucleo_wba55cg/nucleo_wba55cg.dts

@@ -19,6 +19,7 @@
 	#size-cells = <1>;
 
 	chosen {
+		zephyr,bt-c2h-uart = &usart1;
 		zephyr,console = &usart1;
 		zephyr,shell-uart = &usart1;
 		zephyr,sram = &sram0;