MAINTAINERS: change Atmel ssc driver entry

I take over the maintainship from Voice.

Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Cc: Mark Brown <broonie@linaro.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Acked-by: Bo Shen <voice.shen@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>