layer.conf: Update to whinlatter (5.3) layer/release series

LAYERSERIES_COMPAT: switch to whinlatter Yocto 5.3.
Drop styhead and walnascar due to UNPACKDIR/WORKDIR changes.

Signed-off-by: Geoff Parker <geoffrey.parker@arthrex.com>

conf/layer.conf

@@ -9,6 +9,6 @@ BBFILE_COLLECTIONS += "swupdate"
 BBFILE_PATTERN_swupdate := "^${LAYERDIR}/"
 BBFILE_PRIORITY_swupdate = "6"
 
-LAYERSERIES_COMPAT_swupdate = "styhead walnascar"
+LAYERSERIES_COMPAT_swupdate = "whinlatter"
 
 LAYERDEPENDS_swupdate = "openembedded-layer"