MAINTAINERS: Update Benjamin Gaignard maintainer status

Update Benjamin Gaignard address and remove it from no more maintained
drivers.

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@collabora.com>
Reviewed-by: Philippe Cornu <philippe.cornu@foss.st.com>
Link: https://lore.kernel.org/r/20220113171921.17466-2-philippe.cornu@foss.st.com

'
Signed-off-by: Arnd Bergmann <arnd@arndb.de>