Define selinux context for econtroller.

Bug: 33075886
Test: N/A
Change-Id: I1654ee20fa6125cf3ed5c0796e85f289db5a9745

private/service_contexts

@@ -45,6 +45,7 @@ dreams                                    u:object_r:dreams_service:s0
 drm.drmManager                            u:object_r:drmserver_service:s0
 dropbox                                   u:object_r:dropbox_service:s0
 dumpstate                                 u:object_r:dumpstate_service:s0
+econtroller                               u:object_r:radio_service:s0
 ethernet                                  u:object_r:ethernet_service:s0
 fingerprint                               u:object_r:fingerprint_service:s0
 font                                      u:object_r:font_service:s0