SELinux policy: let vold setsched of kernel processes.

Change-Id: I2b7bf3037c94de4fecf3c3081497e0ac1dfef8a9

vold.te

@@ -56,6 +56,9 @@ allow vold proc:file write;
 # Create and mount on /data/tmp_mnt.
 allow vold system_data_file:dir { rw_dir_perms mounton };
 
+# Set scheduling policy of kernel processes
+allow vold kernel:process setsched;
+
 # Property Service
 allow vold vold_prop:property_service set;