wic: add 'none' fstype for custom image

It's not possible to set the label (of gpt entry) normally
when I want to use non-listed fstype as a rawcopy.

Example)
part ? --source rawcopy --ondisk mmcblk0 --label mypart --sourceparams file=mypart.raw

To resolve this problem, this patch addes a 'none' fstype
and ignore do_image_label on rawcopy (that actually set the partition label.)

(From OE-Core rev: 949cf797eb54f3d22a093910087e937633ce9b23)

Signed-off-by: JeongBong Seo <jb.seo@lge.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

scripts/lib/wic/plugins/source/rawcopy.py

@@ -25,6 +25,10 @@ class RawCopyPlugin(SourcePlugin):
 
     @staticmethod
     def do_image_label(fstype, dst, label):
+        # don't create label when fstype is none
+        if fstype == 'none':
+            return
+
         if fstype.startswith('ext'):
             cmd = 'tune2fs -L %s %s' % (label, dst)
         elif fstype in ('msdos', 'vfat'):