This way the modifier path gets exercised all the time, improving
testing. Furthermore, for modifiers this is required as getfb2
will always return the modifier if the driver sets allow_fb_modifiers.

This only triggers once allow_fb_modifiers is set.
Signed-off-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>