Add Shradha Shah as the sfc driver maintainer.

I will be taking over the work from Ben Hutchings.

Signed-off-by: Shradha Shah <sshah@solarflare.com>
Acked-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>