raspberrypi inclusion
category: feature
bugzilla: 50432

------------------------------

This patch adjusts following kbuild related patches for
raspberry pi on non-Raspberry Pi platforms, using specific
config CONFIG_OPENEULER_RASPBERRYPI to distinguish them:

d2864887 Kbuild: Allow .dtbo overlays to be built, adjust.
0131a56e kbuild: Disable gcc plugins
4894352e kbuild: Silence unavoidable dtc overlay warnings
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>
Reviewed-by: NXie XiuQi <xiexiuqi@huawei.com>