ref-manual: Add vfat in list of filesystems supported by kickstart

(From yocto-docs rev: 6e09a7eb190c412fa282bde128a6f8f1b24fd713)

Signed-off-by: Daniel Ammann <daniel.ammann@bytesatwork.ch>
Reviewed-by: Michael Opdenacker <michael.opdenacker@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

documentation/ref-manual/kickstart.rst

@@ -125,6 +125,8 @@ the ``part`` and ``partition`` commands:
 
    -  ``swap``
 
+   -  ``vfat``
+
 -  ``--fsoptions``: Specifies a free-form string of options to be used
    when mounting the filesystem. This string is copied into the
    ``/etc/fstab`` file of the installed system and should be enclosed in