Allow init to configure dm_verity kernel driver.

To disable hash-tree prefetching.

Bug: 136247322
Test: atest google/perf/boottime/boottime-test
Change-Id: Ibdcb88d1014f58918119867c6d701dc58af0c049
diff --git a/private/genfs_contexts b/private/genfs_contexts
index 5b956da..fa49dd9 100644
--- a/private/genfs_contexts
+++ b/private/genfs_contexts
@@ -145,6 +145,7 @@
 genfscon sysfs /kernel/notes u:object_r:sysfs_kernel_notes:s0
 genfscon sysfs /kernel/uevent_helper u:object_r:sysfs_usermodehelper:s0
 genfscon sysfs /kernel/wakeup_reasons u:object_r:sysfs_wakeup_reasons:s0
+genfscon sysfs /module/dm_verity/parameters/prefetch_cluster u:object_r:sysfs_dm_verity:s0
 genfscon sysfs /module/lowmemorykiller u:object_r:sysfs_lowmemorykiller:s0
 genfscon sysfs /module/tcp_cubic/parameters u:object_r:sysfs_net:s0
 genfscon sysfs /module/wlan/parameters/fwpath u:object_r:sysfs_wlan_fwpath:s0