Allow ueventd to read apex mount directories.

ueventd now scans /apex/*/firmware/ directories to find firmwares.

Bug: 167942098
Test: loading firmware from vibrator apex (sunfish)
Change-Id: I76e32e3c290fa07307377bc6fbea41c1783e40a6
diff --git a/public/ueventd.te b/public/ueventd.te
index 1d75080..9c2575a 100644
--- a/public/ueventd.te
+++ b/public/ueventd.te
@@ -31,6 +31,9 @@
 # Access for /vendor/ueventd.rc and /vendor/firmware
 r_dir_file(ueventd, { vendor_file_type -vendor_app_file -vendor_overlay_file })
 
+# Access for /apex/*/firmware
+allow ueventd apex_mnt_dir:dir r_dir_perms;
+
 # Get file contexts for new device nodes
 allow ueventd file_contexts_file:file r_file_perms;