Revert "Remove the bdev_type and sysfs_block_type SELinux attributes"

This reverts commit 63930d3850b1592c3a0a84734777232e81228412.

Reason for revert: Broken build (https://android-build.googleplex.com/builds/submitted/7863094/aosp_raven-userdebug/latest/view/logs/error.log)

Change-Id: I1742d69d471e9b00359a2e7e654aa752513990df
diff --git a/private/genfs_contexts b/private/genfs_contexts
index 8f82b5d..664a3b3 100644
--- a/private/genfs_contexts
+++ b/private/genfs_contexts
@@ -119,6 +119,7 @@
 genfscon sysfs /devices/system/cpu u:object_r:sysfs_devices_system_cpu:s0
 genfscon sysfs /class/android_usb                 u:object_r:sysfs_android_usb:s0
 genfscon sysfs /class/extcon                      u:object_r:sysfs_extcon:s0
+genfscon sysfs /class/block                       u:object_r:sysfs_block:s0
 genfscon sysfs /class/leds                        u:object_r:sysfs_leds:s0
 genfscon sysfs /class/net                         u:object_r:sysfs_net:s0
 genfscon sysfs /class/rfkill/rfkill0/state        u:object_r:sysfs_bluetooth_writable:s0