MAINTAINERS: i2c: at91: handover maintenance to Codrin Ciubotariu

My colleague Codrin Ciubotariu, now, maintains this driver internally.
Then I handover the mainline maintenance to him.

Signed-off-by: Ludovic Desroches <ludovic.desroches@microchip.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>