CI: remove obsolete linux-yocto workarounds

Now we're using master these workarounds are not needed anymore.

Signed-off-by: Ross Burton <ross.burton@arm.com>
Signed-off-by: Jon Mason <jon.mason@arm.com>

ci/clang.yml

@@ -12,8 +12,3 @@ repos:
 local_conf_header:
   clang: |
     TOOLCHAIN = "clang"
-    # Backport d89e06ad94a46f6810d0a8787004b71b8ecaf87d to langdale
-    OBJCOPY:pn-linux-yocto:toolchain-clang = "${HOST_PREFIX}objcopy"
-    # Perf needs fixes backported, use GCC for now
-    # https://lore.kernel.org/linux-perf-users/Y5d4k7fDxfRP7hcN@kernel.org/T/#t
-    TOOLCHAIN:pn-perf = "gcc"