Add the /dev/diag file context.

Change-Id: I57d8ad8380f9722cb19220c7bbf5803f530bbc0b
diff --git a/sepolicy/file_contexts b/sepolicy/file_contexts
index 6d36f25..8e5db5c 100644
--- a/sepolicy/file_contexts
+++ b/sepolicy/file_contexts
@@ -7,3 +7,4 @@
 
 /dev/socket/qmux_radio/*           u:object_r:qmux_socket:s0
 /dev/bcm2079x-i2c                  u:object_r:bcm2079x_device:s0
+/dev/diag                          u:object_r:diag_device:s0