arm/classes: add apply_local_src_patches task

When a recipe uses the externalsrc class, the do_patch task is
skipped entirely as specified in SRCTREECOVEREDTASKS.
Since do_apply_local_src_patches function is registered as a postfuncs,
it would never run in that specific case.

This cause recipes relying on do_apply_local_src_patches to miss the
local source patching when built from external source tree.

To address the issue, schedule a new task after the do_patch and before
the do_configure, ensuring the local patching executes regardless of
whether do_patch was skipped by externalsrc.

Signed-off-by: Clement Faure <clement.faure@arm.com>
Signed-off-by: Jon Mason <jon.mason@arm.com>

meta-arm/classes/apply_local_src_patches.bbclass

@@ -50,4 +50,4 @@ apply_local_src_patches() {
 do_apply_local_src_patches() {
     apply_local_src_patches "${LOCAL_SRC_PATCHES_INPUT_DIR}" "${LOCAL_SRC_PATCHES_DEST_DIR}"
 }
-do_patch[postfuncs] += "do_apply_local_src_patches"
+addtask apply_local_src_patches after do_patch before do_configure