kms_vaapi: add cursor capture for amd/intel monitor capture

Always find largest drm buf, to fix some cases
when there are multiple planes and we accidentally
capture a drm buf that isn't the target buf.
We always want the full SCREEN drm buf.

src/main.cpp

@@ -1384,7 +1384,6 @@ int main(int argc, char **argv) {
             }
 
             gsr_capture_kms_vaapi_params kms_params;
-            kms_params.dpy = dpy;
             kms_params.display_to_capture = capture_target;
             kms_params.gpu_inf = gpu_inf;
             kms_params.card_path = card_path;