[scarthgap] chromium: Use correct Rust mixin layer dependency (#863)

Fixes #862.

Thanks to @darren-etheridge for finding this as well as the right name to use!

Author: MaxIhlenfeldt

meta-chromium/conf/layer.conf

@@ -11,4 +11,4 @@ BBFILE_PRIORITY_chromium-browser-layer = "7"
 LAYERVERSION_chromium-browser-layer = "1"
 LAYERSERIES_COMPAT_chromium-browser-layer = "scarthgap styhead walnascar"
 
-LAYERDEPENDS_chromium-browser-layer = "clang-layer core openembedded-layer lts-rust-mixin"
+LAYERDEPENDS_chromium-browser-layer = "clang-layer core openembedded-layer scarthgap-rust-mixin"