system_server: TelephonyManager reads /proc/cmdline

Bug: 124466646
Test: build
Change-Id: Ib4868826eb153543c65503bfb4d3623c4158ffae
diff --git a/private/system_server.te b/private/system_server.te
index ab4a07c..35ddbf0 100644
--- a/private/system_server.te
+++ b/private/system_server.te
@@ -832,6 +832,7 @@
 r_dir_file(system_server, proc_net_type)
 r_dir_file(system_server, proc_qtaguid_stat)
 allow system_server {
+  proc_cmdline
   proc_loadavg
   proc_meminfo
   proc_pagetypeinfo