hal_light: add permission to sys/class/leds.

/sys/class/leds is the standard location for linux files dealing with
leds, however the exact contents of this directory is non-standard
(hence the need for a hal).

Bug: 32022100
Test: compiles and works for the subset of common files
Change-Id: I7571d7267d5ed531c4cf95599d5f2acc22287ef4
diff --git a/private/file_contexts b/private/file_contexts
index 0ca1c58..16ecbf0 100644
--- a/private/file_contexts
+++ b/private/file_contexts
@@ -419,6 +419,7 @@
 #############################
 # sysfs files
 #
+/sys/class/leds(/.*)?                        u:object_r:sysfs_leds:s0
 /sys/devices/platform/nfc-power/nfc_power -- u:object_r:sysfs_nfc_power_writable:s0
 /sys/devices/system/cpu(/.*)?    u:object_r:sysfs_devices_system_cpu:s0
 /sys/devices/virtual/block/zram\d+(/.*)?     u:object_r:sysfs_zram:s0