procd: do not overwrite service data by default

Allows a running servie to manage its own data if untouched by the init script

Signed-off-by: Felix Fietkau <nbd@nbd.name>
(cherry picked from commit 8c5826b140)

package/base-files/files/etc/rc.common

@@ -100,10 +100,6 @@ service_triggers() {
 	return 0
 }
 
-service_data() {
-	return 0
-}
-
 service_running() {
 	local instance="${1:-*}"