wireplumber: enable systemd service

Add SYSTEMD_SERVICE variable to register wireplumber.service with
systemd to enable automatic service startup and management.

Signed-off-by: Paresh Bhagat <p-bhagat@ti.com>
Signed-off-by: Khem Raj <khem.raj@oss.qualcomm.com>

meta-multimedia/recipes-multimedia/wireplumber/wireplumber_0.5.18.bb

@@ -164,6 +164,8 @@ RRECOMMENDS:${PN} += "pipewire ${PN}-scripts ${PN}-modules-meta"
 
 FILES:${PN} += "${systemd_user_unitdir} ${systemd_system_unitdir} ${datadir}/zsh"
 
+SYSTEMD_SERVICE:${PN} = "wireplumber.service"
+
 FILES:libwireplumber = " \
     ${libdir}/libwireplumber-*.so.* \
 "