drm/xe: select X86_PLATFORM_DEVICES when ACPI_WMI is selected

drm/xe: select X86_PLATFORM_DEVICES when ACPI_WMI is selected

ACPI_WMI is a subitem of X86_PLATFORM_DEVICES. And X86_PLATFORM_DEVICES
is not selected in the current Kconfig, and may cause Kconfig warnings:

WARNING: unmet direct dependencies detected for ACPI_WMI
  Depends on [n]: X86_PLATFORM_DEVICES [=n] && ACPI [=y]
  Selected by [m]:
  - DRM_XE [=m] && HAS_IOMEM [=y] && DRM [=m] && PCI [=y] && MMU [=y] &&
    (m && MODULES [=y] || y && KUNIT [=y]=y) && X86 [=y] && ACPI [=y]

Signed-off-by: Lu Yao <yaolu@kylinos.cn>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240415025215.15811-1-yaolu@kylinos.cn
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>