CI: remove meta-clang

Now that clang is in core, we don't need to use meta-clang anymore.
Also, use PREFERRED_TOOLCHAIN_TARGET to specify the toolchain to use.

Signed-off-by: Jon Mason <jon.mason@arm.com>

ci/clang.yml

@@ -3,10 +3,6 @@
 header:
   version: 14
 
-repos:
-  meta-clang:
-    url: https://github.com/kraj/meta-clang
-
 local_conf_header:
   toolchain: |
-    TOOLCHAIN = "clang"
+    PREFERRED_TOOLCHAIN_TARGET = "clang"

ci/gcc.yml

@@ -3,7 +3,7 @@
 header:
   version: 14
 
-#NOTE: This is the default for poky.  This is only being added for completeness/clarity
+#NOTE: This is the default.  This is only being added for completeness/clarity
 local_conf_header:
   toolchain: |
-    TOOLCHAIN = "gcc"
+    PREFERRED_TOOLCHAIN_TARGET = "gcc"

ci/update-repos

@@ -23,7 +23,6 @@ repositories = (
     "https://git.yoctoproject.org/poky",
     "https://git.openembedded.org/meta-openembedded",
     "https://git.yoctoproject.org/meta-virtualization",
-    "https://github.com/kraj/meta-clang",
 )
 
 if __name__ == "__main__":