Clarify how to pass the field width for bitmaps, and mention the helper
macros that are available to ease printing cpumask and nodemask.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20201110144121.3278667-1-geert+renesas@glider.beSigned-off-by: Jonathan Corbet <corbet@lwn.net>