Allow ROOT_UID to execute privileged shell cmds

When adb runs as root, Binder.getCallingUid returns ROOT_UID for shell
commands. Add that to the allow list.

Test: manual
Change-Id: I8457500e2272110496ae7054347490863a446dce
diff --git a/src/com/android/phone/TelephonyShellCommand.java b/src/com/android/phone/TelephonyShellCommand.java
index dc1e7d1..dac797d 100644
--- a/src/com/android/phone/TelephonyShellCommand.java
+++ b/src/com/android/phone/TelephonyShellCommand.java
@@ -439,6 +439,8 @@
     }
 
     private boolean checkShellUid() {
-        return Binder.getCallingUid() == Process.SHELL_UID;
+        // adb can run as root or as shell, depending on whether the device is rooted.
+        return Binder.getCallingUid() == Process.SHELL_UID
+                || Binder.getCallingUid() == Process.ROOT_UID;
     }
 }