ci: enable esp32s3_devkitm testing

Fix wrong board name.

Signed-off-by: Sylvio Alves <sylvio.alves@espressif.com>

Author: sylvioalves

.github/workflows/ci.yml

@@ -1523,8 +1523,7 @@ jobs:
               PLATFORM_ARGS+="-p esp32s2_saola "
               ;;
             xtensa-espressif_esp32s3_zephyr-elf)
-              # FIXME: Disabled until esp32s3_devkitc board is upstreamed.
-              # PLATFORM_ARGS+="-p esp32s3_devkitc "
+              PLATFORM_ARGS+="-p esp32s3_devkitm "
               ;;
             xtensa-intel_apl_adsp_zephyr-elf)
               PLATFORM_ARGS+="-p intel_adsp_cavs15 "