oniro-openharmony-linux.conf: Use systemd as PID 1

We are going to use systemd to integrate OpenHarmony services with the rest of
the Linux system.

Signed-off-by: Esben Haabendal <esben.haabendal@huawei.com>

conf/distro/oniro-openharmony-linux.conf

@@ -21,6 +21,8 @@ SDKIMAGE_FEATURES:append = " staticdev-pkgs"
 ONIRO_OPENHARMONY_DEFAULT_DISTRO_FEATURES = "ipv4 ptest"
 DISTRO_FEATURES ?= "${ONIRO_OPENHARMONY_DEFAULT_DISTRO_FEATURES}"
 
+INIT_MANAGER = "systemd"
+
 # Linux kernel version
 PREFERRED_VERSION_linux-yocto = "5.10.%"