drm/meson: Allow build with COMPILE_TEST=y

Allow meson to be built with COMPILE_TEST=y for greater
coverage. Builds fine on x86/x86_64 at least.

Cc: Neil Armstrong <neil.armstrong@linaro.org>
Cc: linux-amlogic@lists.infradead.org
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241003111851.10453-11-ville.syrjala@linux.intel.com


Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>