layer.conf: Remove dependancy on meta-arm-toolchain

Keeping things simple for what we're doing this dependancy isn't
required.

Signed-off-by: Eilís Ní Fhlannagáin <elizabeth.flanagan@huawei.com>

meta-arm/conf/layer.conf

@@ -11,7 +11,6 @@ BBFILE_PRIORITY_meta-arm = "5"
 
 LAYERDEPENDS_meta-arm = " \
     core \
-    arm-toolchain \
 "
 LAYERSERIES_COMPAT_meta-arm = "dunfell"