compositor-drm: Fall back if GBM surface fails with modifiers
If we cannot create a gbm_surface using a list of modifiers, fall back to using the old pre-modifier version.
This fixes initialisation on systems where KMS supports modifiers but the GBM driver does not, such as old i915 systems like Pine View using the unified KMS driver but the old i915 Mesa driver.
Signed-off-by: Daniel Stone daniels@collabora.com