MAINTAINERS: net: wilc1000: Update entry

As Adham's email address is bouncing, remove him from wilc1000 entry and
add Claudiu as a new co-maintainer. Claudiu follows wilc1000 driver
development for a long time and contributed to it already.

Signed-off-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Signed-off-by: Ajay Singh <ajay.kathat@microchip.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20200710051826.3267-2-ajay.kathat@microchip.com