imx8mq_evk: Add myself as a co-maintainer

I would like to help maintaining this board.
Signed-off-by: NFabio Estevam <festevam@gmail.com>
Acked-by: NPeng Fan <peng.fan@nxp.com>

board/freescale/imx8mq_evk/MAINTAINERS

 i.MX8MQ EVK BOARD
 M:	Peng Fan <peng.fan@nxp.com>
+M:	Fabio Estevam <festevam@gmail.com>
 S:	Maintained
 F:	board/freescale/imx8mq_evk/
 F:	include/configs/imx8mq_evk.h