sepolicy : removed coredomain access to vendor_files

As part of treble coredomain are not allowed to access
vendor_files .Where neverallow has been added as part
of treble restriction . This change is cleaning
coredomains access to following type
 firmware_file
 adsprpcd_file
 vendor_carrier_file

Change-Id: Ic98f26223cc58dbbe3fa862a9b1bc4bec1c8eded