comedi: Annotate struct comedi_lrange with __counted_by

Prepare for the coming implementation by GCC and Clang of the __counted_by
attribute. Flexible array members annotated with __counted_by can have
their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS
(for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
functions).

Signed-off-by: Christophe JAILLET <[e-mail]>
Reviewed-by: Kees Cook <[e-mail]>
Reviewed-by: "Gustavo A. R. Silva" <[e-mail]>
Link: https://lore.kernel.org/r/5c3b7459b8[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

include/linux/comedi/comedidev.h

···
  */
 struct comedi_lrange {
 	int length;
-	struct comedi_krange range[];
+	struct comedi_krange range[] __counted_by(length);
 };
 
 /**