tests: drivers: uart: uart_elementary: update testcase.yaml

Add some STM32 platforms to the allowed list to perform a
specific scenario.

Signed-off-by: Fabrice DJIATSA <[email protected]>

Author: djiatsaf-st

tests/drivers/uart/uart_elementary/testcase.yaml

@@ -28,6 +28,14 @@ tests:
       - xg24_rb4187c
       - bg29_rb4420a
       - xg29_rb4412a
+      - b_u585i_iot02a
+      - nucleo_f091rc
+      - nucleo_g071rb
+      - nucleo_g474re
+      - nucleo_h743zi
+      - nucleo_l152re
+      - stm32n6570_dk/stm32n657xx/sb
+      - stm32u083c_dk
     integration_platforms:
       - nrf54h20dk/nrf54h20/cpuapp
   drivers.uart.uart_elementary_dual_nrf54h: