layer.conf: branch for scarthgap

Signed-off-by: Mark Hatle <mark.hatle@amd.com>

conf/layer.conf

@@ -12,18 +12,7 @@ BBFILE_PRIORITY_openamp-layer = "5"
 # cause compatibility issues with other layers
 LAYERVERSION_openamp-layer = "1"
 
-# meta-openamp upstream master branch supports:
-# = POLICY ======== CURRENT RELEASE ===
-# master            scarthgap   YP 5.0 2024/04
-# latest release    nanbield    YP 4.3 2023/10
-# LTS               kirkstone   YP 4.0 2022/04
-#
-# Upstream also supports the following via the appropriate branch:
-# (LTS-1)           dunfell     YP 3.1 2020/04
-LAYERSERIES_COMPAT_openamp-layer = "kirkstone nanbield scarthgap"
-
-# only for Xilinx petalinux
-LAYERSERIES_COMPAT_openamp-layer += "langdale"
+LAYERSERIES_COMPAT_openamp-layer = "scarthgap"
 
 # set layer path for this layer only
 LAYER_PATH_openamp-layer = "${LAYERDIR}"