Label /proc/config.gz

Add a label to /proc/config.gz, so we can distinguish this file from
other /proc files in security policy.

For now, only init is allowed read access. All others are denied.
TODO: clarify exactly who needs access. Further access will be granted
in a future commit.

Bug: 35126415
Test: policy compiles and no device boot problems.
Change-Id: I8b480890495ce5b8aa3f8c7eb00e14159f177860
diff --git a/private/genfs_contexts b/private/genfs_contexts
index efdfb42..0c50675 100644
--- a/private/genfs_contexts
+++ b/private/genfs_contexts
@@ -2,6 +2,7 @@
 genfscon rootfs / u:object_r:rootfs:s0
 # proc labeling can be further refined (longest matching prefix).
 genfscon proc / u:object_r:proc:s0
+genfscon proc /config.gz u:object_r:config_gz:s0
 genfscon proc /interrupts u:object_r:proc_interrupts:s0
 genfscon proc /iomem u:object_r:proc_iomem:s0
 genfscon proc /meminfo u:object_r:proc_meminfo:s0