modpost: remove stale comment about sym_add_exported()

The description,

  it may have already been added without a
  CRC, in this case just update the CRC

... is no longer valid.

In the old days, this function was used to update the CRC as well.

Commit 040fcc81 ("kbuild: improved modversioning support for
external modules") started to use a separate function (sym_update_crc)
for updating the CRC.

The first part, "Add an exported symbol" is correct, but it is too
obvious from the function name. Drop this comment entirely.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>

scripts/mod/modpost.c

@@ -387,10 +387,6 @@ static void sym_update_namespace(const char *symname, const char *namespace)
 	s->namespace = namespace[0] ? NOFAIL(strdup(namespace)) : NULL;
 }
 
-/**
- * Add an exported symbol - it may have already been added without a
- * CRC, in this case just update the CRC
- **/
 static struct symbol *sym_add_exported(const char *name, struct module *mod,
 				       enum export export)
 {