domain_deprecated: remove ion access

Logs show that only dumpstate requires access.

avc: granted { read open } for comm="screencap" path="/dev/ion"
dev="tmpfs" ino=14324 scontext=u:r:dumpstate:s0
tcontext=u:object_r:ion_device:s0 tclass=chr_file
avc: granted { ioctl } for comm="screencap" path="/dev/ion" dev="tmpfs"
ino=14324 ioctlcmd=4906 scontext=u:r:dumpstate:s0
tcontext=u:object_r:ion_device:s0 tclass=chr_file

Grant ion permission to dumpstate which uses it for screencap
feature.

Bug: 28760354
Test: build. Check logs.
Change-Id: I6435b7dbf7656669dac5dcfb205cf0aeda93991b

public/domain_deprecated.te

@@ -158,25 +158,6 @@ auditallow {
 } cache_file:lnk_file r_file_perms;
 ')
 
-# Allow access to ion memory allocation device
-allow domain_deprecated ion_device:chr_file rw_file_perms;
-# split this auditallow into read and write perms since most domains seem to
-# only require read
-userdebug_or_eng(`
-auditallow {
-  domain_deprecated
-  -appdomain
-  -fingerprintd
-  -keystore
-  -surfaceflinger
-  -system_server
-  -tee
-  -vold
-  -zygote
-} ion_device:chr_file r_file_perms;
-auditallow domain_deprecated ion_device:chr_file { write append };
-')
-
 # Read access to pseudo filesystems.
 r_dir_file(domain_deprecated, proc)
 r_dir_file(domain_deprecated, sysfs)

public/dumpstate.te

@@ -194,6 +194,9 @@ allow dumpstate proc_zoneinfo:file r_file_perms;
 # Create a service for talking back to system_server
 add_service(dumpstate, dumpstate_service)
 
+# use /dev/ion for screen capture
+allow dumpstate ion_device:chr_file r_file_perms;
+
 ###
 ### neverallow rules
 ###