MAINTAINERS: Add Miquel Raynal as additional maintainer for ieee802154

We are growing the maintainer team for ieee802154 to spread the load for
review and general maintenance. Miquel has been driving the subsystem
forward over the last year and we would like to welcome him as a
maintainer.

Signed-off-by: Stefan Schmidt <stefan@datenfreihafen.org>
Acked-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/r/20230218211317.284889-4-stefan@datenfreihafen.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>