MAINTAINERS: Update maintainer entry for wilc1000

MAINTAINERS: Update maintainer entry for wilc1000

Take the maintenance of the Atmel WIFI staging driver wilc1000.
Former maintainers are no more with Atmel.

Reported-by: Loic Lefort <loic.lefort@atmel.com>
Signed-off-by: Aditya Shankar <aditya.shankar@microchip.com>
Signed-off-by: Ganesh Krishna <ganesh.krishna@microchip.com>
Acked-by: Luis de Bethencourt <luisbg@osg.samsung.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>