Fix Traceback in CMSIS export.

The traceback was caused when a file without a parent directory (which
is implicitly ".") is added to the resources object. The code assumed
that all files within the resources object would have a parent
directory.

This commit changes the check to account for files that are in the root
directory of a project and have no preceding `./`

tools/export/cmsis/__init__.py

@@ -121,7 +121,7 @@ class CMSIS(Exporter):
             new_srcs = []
             for f in list(files):
                 spl = f.name.split(sep)
-                if len(spl)==2:
+                if len(spl) <= 2:
                     file_element = Element('file',
                                            attrib={
                                                'category':f.type,
@@ -148,8 +148,4 @@ class CMSIS(Exporter):
             'device': DeviceCMSIS(self.target),
             'date': ''
         }
-        # TODO: find how to keep prettyxml from adding xml version to this blob
-        #dom = parseString(ctx['project_files'])
-        #ctx['project_files'] = dom.toprettyxml(indent="\t")
-
         self.gen_file('cmsis/cpdsc.tmpl', ctx, 'project.cpdsc')