Daniel Stone authored Apr 02, 2018 and Jonas Ådahl committed Apr 03, 2018

If we attempt GBM surface allocation with a set of modifiers but the
allocation fails, fall back to non-modifier allocations. This fixes
startup on Pineview-based Atom systems, where KMS provides us a set of
modifiers but the GBM implementation doesn't support modifier use.

Closes: #84


(cherry picked from commit e6109cfc)