MAINTAINERS: mailmap: update Richard Genoud's email address

I'm working now at bootlin, so I'll use my bootlin address for kernel
development from now on.

Update also the yaml file for atmel-serial accordingly.

Signed-off-by: Richard Genoud <richard.genoud@bootlin.com>
Reviewed-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Link: https://lore.kernel.org/r/20240408101329.9448-1-richard.genoud@bootlin.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>