allow to load kernel modules from vendor partition

The kernel  modules under /vendor partition has been relabeled to vendor_file.
This CL allows for the modprobe to load modules labeled vendor_file.

Kernel modules are loaded in init.rc with following commands:
    exec u:r:modprobe:s0 -- /system/bin/modprobe -d /vendor/lib/modules MODULE

Bug: 35653245
Test: tested on sailfish
Change-Id: I2132ca4de01c5c60476dad8496e98266de5a1bb7

public/domain.te

@@ -994,7 +994,7 @@ neverallow {
 # Enforce restrictions on kernel module origin.
 # Do not allow kernel module loading except from system,
 # vendor, and boot partitions.
-neverallow * ~{ system_file vendor_file_type rootfs }:system module_load;
+neverallow * ~{ system_file vendor_file rootfs }:system module_load;
 
 # Only allow filesystem caps to be set at build time or
 # during upgrade by recovery.

public/modprobe.te

@@ -6,4 +6,5 @@ recovery_only(`
   allow modprobe rootfs:system module_load;
   allow modprobe rootfs:file r_file_perms;
 ')
-allow modprobe system_file:system module_load;
+allow modprobe { system_file vendor_file }:system module_load;
+r_dir_file(modprobe, { system_file vendor_file })