arm64: defconfig: Enable STMicroelectronics STM32 display support

arm64: defconfig: Enable STMicroelectronics STM32 display support

Enable STMicroelectronics STM32 display support as module.
This includes:
  * DRM_STM
  * DRM_STM_LVDS
  * BACKLIGHT_GPIO
  * TOUCHSCREEN_ILI210X

This display is used on several SoCs and boards such as STM32MP257F-EV1
and STM32MP257F-DK.

Signed-off-by: Raphael Gallais-Pou <raphael.gallais-pou@foss.st.com>
Tested-by: Yannick Fertre <yannick.fertre@foss.st.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
Link: https://lore.kernel.org/r/20260205-master-v1-1-dcefcabc2934@foss.st.com
Signed-off-by: Alexandre Torgue <alexandre.torgue@foss.st.com>