mt6765-common: sepolicy: Allow recovery init to write to sysfs_devices_block

 - Re-labeling it doesn't seem to work.
 - This addresses https://katb.in/uyoqiligace, which is basically allowing recovery to write to preloader block for fw upgrade.

Change-Id: I52a6df5cfa8dbcc35f3cff6c33c4fb5c731fd251