drm/xe: Disable 32bits build

Add a dependency on CONFIG_64BIT since currently the xe driver doesn't
build on 32bits. It may be enabled again after all the issues are fixed.

Fixes: dd08ebf6 ("drm/xe: Introduce a new DRM driver for Intel GPUs")
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://lore.kernel.org/r/20231221222809.4123220-2-lucas.demarchi@intel.com


Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>