linux: include rauc config snippet in linux-raspberry_%.bbappend

This enables configuration pieces required for RAUC verity bundles.

Signed-off-by: Zygmunt Krynicki <zygmunt.krynicki@huawei.com>

meta-oniro-core/recipes-kernel/linux/linux-raspberrypi_%.bbappend

@@ -4,4 +4,7 @@
 
 FILESEXTRAPATHS:prepend := "${THISDIR}/linux:"
 
-SRC_URI += "file://squashfs.cfg"
+SRC_URI += "\
+    file://squashfs.cfg \
+    file://rauc.cfg \
+    "