Define policy for /proc/uid_io/stats

New procfs file read by storaged to dump fg/bg IO usage.

Remove kmsg rule since it's no longer used by storaged.

Allow storaged to find permission_service to translate UID
to package name.

Test: adb shell storaged -u
Bug: 34198239
Change-Id: I74654662c75571cbe166cf2b8cbab84828218cbd
diff --git a/private/genfs_contexts b/private/genfs_contexts
index 6386101..efdfb42 100644
--- a/private/genfs_contexts
+++ b/private/genfs_contexts
@@ -32,6 +32,7 @@
 genfscon proc /tty/drivers u:object_r:proc_tty_drivers:s0
 genfscon proc /uid_cputime/show_uid_stat u:object_r:proc_uid_cputime_showstat:s0
 genfscon proc /uid_cputime/remove_uid_range u:object_r:proc_uid_cputime_removeuid:s0
+genfscon proc /uid_io/stats u:object_r:proc_uid_io_stats:s0
 genfscon proc /uid_procstat/set u:object_r:proc_uid_procstat_set:s0
 genfscon proc /zoneinfo u:object_r:proc_zoneinfo:s0