kms: Do not attempt to import dmabuf on device not supporting format

Previously, if `expected_node` couldn't import a buffer, it would print
an error, then try the next node. There shouldn't really be a reason to
attempt import if the format/modifier isn't in `dmabuf_texture_formats`.

It seems the issue I've been seeing with cosmic-workspaces crashing
the Nvidia driver is fixed by removing this, and disabling `dma_shadow_copy`
(which was producing the same error). Importing Nvidia buffers on the AMD
GPU seems to be causing issues.

Not sure how `dma_shadow_copy` should be fixed, but a test for supported
formats is easy to add here anyway.

src/backend/kms/mod.rs

@@ -16,6 +16,7 @@ use smithay::{
         allocator::{
             dmabuf::Dmabuf,
             gbm::{GbmAllocator, GbmBufferFlags},
+            Buffer,
         },
         drm::{output::DrmOutputRenderElements, DrmDeviceFd, DrmNode, NodeType},
         egl::{context::ContextPriority, EGLContext, EGLDevice, EGLDisplay},
@@ -456,6 +457,17 @@ impl KmsState {
                 &_egl.as_ref().unwrap().display
             };
 
+            if !egl_display
+                .dmabuf_texture_formats()
+                .contains(&dmabuf.format())
+            {
+                trace!(
+                    "Skipping import of dmabuf on {:?}: unsupported format",
+                    device.render_node
+                );
+                continue;
+            }
+
             let result = egl_display
                 .create_image_from_dmabuf(&dmabuf)
                 .map(|image| {