docs: kerneldoc.py: add support for kerneldoc -nosymbol

Currently, there's no way to exclude identifiers from
a kernel-doc markup. Add support for it.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
diff --git a/Documentation/sphinx/kerneldoc.py b/Documentation/sphinx/kerneldoc.py
index a3a5427..e9857ab 100644
--- a/Documentation/sphinx/kerneldoc.py
+++ b/Documentation/sphinx/kerneldoc.py
@@ -62,6 +62,7 @@
         'export': directives.unchanged,
         'internal': directives.unchanged,
         'identifiers': directives.unchanged,
+        'no-identifiers': directives.unchanged,
         'functions': directives.unchanged,
     }
     has_content = False
@@ -104,6 +105,12 @@
             else:
                 cmd += ['-no-doc-sections']
 
+        if 'no-identifiers' in self.options:
+            no_identifiers = self.options.get('no-identifiers').split()
+            if no_identifiers:
+                for i in no_identifiers:
+                    cmd += ['-nosymbol', i]
+
         for pattern in export_file_patterns:
             for f in glob.glob(env.config.kerneldoc_srctree + '/' + pattern):
                 env.note_dependency(os.path.abspath(f))