Add exFAT support; unify behind "sdcard_type".

We're adding support for OEMs to ship exFAT, which behaves identical
to vfat.  Some rules have been manually enumerating labels related
to these "public" volumes, so unify them all behind "sdcard_type".

Test: atest
Bug: 67822822
Change-Id: I09157fd1fc666ec5d98082c6e2cefce7c8d3ae56
diff --git a/private/platform_app.te b/private/platform_app.te
index 80b20e1..f60597a 100644
--- a/private/platform_app.te
+++ b/private/platform_app.te
@@ -34,8 +34,8 @@
 # Direct access to vold-mounted storage under /mnt/media_rw
 # This is a performance optimization that allows platform apps to bypass the FUSE layer
 allow platform_app mnt_media_rw_file:dir r_dir_perms;
-allow platform_app vfat:dir create_dir_perms;
-allow platform_app vfat:file create_file_perms;
+allow platform_app sdcard_type:dir create_dir_perms;
+allow platform_app sdcard_type:file create_file_perms;
 
 # com.android.systemui
 allow platform_app rootfs:dir getattr;