ukify: fix handling signed kernel as file

The .linux section would contain the path to the signed kernel (instead of the signed kernel itself), since the python type of the variable is used to determine how it is handled when adding the pe sections.

Co-authored-by: Otto Bittner <cobittner@posteo.net>

src/ukify/ukify.py

@@ -635,7 +635,7 @@ def make_uki(opts):
 
     if sign_kernel:
         linux_signed = tempfile.NamedTemporaryFile(prefix='linux-signed')
-        linux = linux_signed.name
+        linux = pathlib.Path(linux_signed.name)
         sign(sign_tool, opts.linux, linux, opts=opts)
     else:
         linux = opts.linux