remount: allow bootanimation to run animation from oem

Grant bootanimation all read permissions on oem using
r_dir_file macro instead of specifying individual permissions.

This prevents failure to read the bootanimation on oem if
partition has been remounted.

After remount, bootanimation will log violation for the
/oem/media directory when reading an existing file (boot animation can
is still played).
avc:  denied  { read } for  pid=2820 comm="bootanimation" name="media"
   dev="sda75" ino=152 scontext=u:r:bootanim:s0
   tcontext=u:object_r:oemfs:s0 tclass=dir permissive=0

After remount, if modifying/adding file in /oem/media directory,
bootanimation will fail to read the bootanimation zip, now with
violation:
avc:  denied  { read } for  pid=2838 comm="bootanimation" name="media"
   dev="dm-8" ino=70 scontext=u:r:bootanim:s0 tcontext=u:object_r:oemfs:s0
   tclass=dir permissive=0

Bug: 324437684
Test: adb remount
      replace /oem/media/bootanimation.zip with custom animation
      adb reboot
      confirm that expected bootanimation is played
      confirm no selinux violations are seen in logcat
Change-Id: Iaafdeeacaf88d8f5c1214700edc8eec2824b0159
diff --git a/public/bootanim.te b/public/bootanim.te
index 9c7a0ee..a9616b7 100644
--- a/public/bootanim.te
+++ b/public/bootanim.te
@@ -17,8 +17,7 @@
 allow bootanim sysfs_gpu:file r_file_perms;
 
 # /oem access
-allow bootanim oemfs:dir search;
-allow bootanim oemfs:file r_file_perms;
+r_dir_file(bootanim, oemfs);
 
 allow bootanim audio_device:dir r_dir_perms;
 allow bootanim audio_device:chr_file rw_file_perms;