sepolicy: Added allow rule for uevent to open/read/getattr on

persist_file and wifi_data_file

This is needed for uevent to start and do a wcnss nvbin
download  if it fails to do will make the wcnss to crash and reboot
the target (related to persist_file access) . wifi_data_file
access is needed for starting the wifi driver.

Change-Id: Id59ef6b0b013c1f61809c7e4bc0513e70407fd8e