Fix rendering on Catacomb

[chrisduerr]

For some reason rendering the browser engine's EGL image works on Sway, but it does not work on Smithay compositors.

[chrisduerr]

The following patch to the FDO backend fixes this issue:

diff --git a/src/ws-egl.cpp b/src/ws-egl.cpp
index b91e4dd..22d988e 100644
--- a/src/ws-egl.cpp
+++ b/src/ws-egl.cpp
@@ -304,8 +304,13 @@ void ImplEGL::foreachDmaBufModifier(std::function<void (int format, uint64_t mod
             modifiers[0] = DRM_FORMAT_MOD_INVALID;
         }

-        for (int j = 0; j < numModifiers; j++)
+        for (int j = 0; j < numModifiers; j++) {
+            if (modifiers[j] != DRM_FORMAT_MOD_LINEAR) {
+                continue;
+            }
+
             callback(formats[i], modifiers[j]);
+        }
     }
 }