imx: mx51evk: drop Stefano Babic from MAINTAINERS

I haven't anymore the MX51EVK board.

Signed-off-by: Stefano Babic <sbabic@nabladev.com>
CC: Fabio Estevam <festevam@gmail.com>
diff --git a/board/freescale/mx51evk/MAINTAINERS b/board/freescale/mx51evk/MAINTAINERS
index 1ca55f7..025a5f8 100644
--- a/board/freescale/mx51evk/MAINTAINERS
+++ b/board/freescale/mx51evk/MAINTAINERS
@@ -1,6 +1,5 @@
 MX51EVK BOARD
 M:	Fabio Estevam <festevam@gmail.com>
-M:	Stefano Babic <sbabic@denx.de>
 S:	Maintained
 F:	board/freescale/mx51evk/
 F:	include/configs/mx51evk.h