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>

Documentation/doc-guide/kernel-doc.rst

@@ -490,6 +490,14 @@ identifiers: *[ function/type ...]*
     .. kernel-doc:: lib/idr.c
        :identifiers:
 
+no-identifiers: *[ function/type ...]*
+  Exclude documentation for each *function* and *type* in *source*.
+
+  Example::
+
+    .. kernel-doc:: lib/bitmap.c
+       :no-identifiers: bitmap_parselist
+
 functions: *[ function/type ...]*
   This is an alias of the 'identifiers' directive and deprecated.
 

Documentation/sphinx/kerneldoc.py

@@ -62,6 +62,7 @@ class KernelDocDirective(Directive):
         'export': directives.unchanged,
         'internal': directives.unchanged,
         'identifiers': directives.unchanged,
+        'no-identifiers': directives.unchanged,
         'functions': directives.unchanged,
     }
     has_content = False
@@ -104,6 +105,12 @@ class KernelDocDirective(Directive):
             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))