nios2: add 3c120 and 10m50 devboards MAINTAINERS

Add 3c120 and 10m50 devboards MAINTAINERS

Signed-off-by: Thomas Chou <thomas@wytron.com.tw>
Acked-by: Marek Vasut <marex@denx.de>

board/altera/nios2/MAINTAINERS

+3C120 DEVBOARD
+M:	Thomas Chou <thomas@wytron.com.tw>
+S:	Maintained
+F:	arch/nios2/dts/3c120_devboard.dts
+F:	configs/3c120_defconfig
+F:	include/configs/3c120_devboard.h
+
+10M50 DEVBOARD
+M:	Thomas Chou <thomas@wytron.com.tw>
+S:	Maintained
+F:	arch/nios2/dts/10m50_devboard.dts
+F:	configs/10m50_defconfig
+F:	include/configs/10m50_devboard.h