main/postmarketos-mkinitfs: include vfat in initfs by default (MR 3166)

An increasing number of devices relies on the vfat file system in the
initfs (e.g. for UEFI boot). Having to add all the modules required for
it to work to deviceinfo_modules_initfs is annoying and inconsistent,
in particular for the additionally chosen "nls" modules. Since we
already bundle several file systems by default, let's just add vfat
as well to simplify this.

Ideally mkinitfs should detect the file systems chosen at install time
in the future and only include the necessary modules, but until then
this just adds a couple of kilobytes to the initramfs.

main/postmarketos-mkinitfs/00-default.modules

@@ -8,3 +8,7 @@ libaes
 aes
 evdev
 btrfs
+vfat
+nls_cp437
+nls_iso8859_1
+nls_utf8