mcx: update maintainer and convert to generic board

Remove obsolete email address from MAINTAINERS.

Signed-off-by: Anatolij Gustschin <agust@denx.de>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Tom Rini <trini@konsulko.com>
diff --git a/include/configs/mcx.h b/include/configs/mcx.h
index 3fd3184..de7792a 100644
--- a/include/configs/mcx.h
+++ b/include/configs/mcx.h
@@ -25,6 +25,8 @@
 #define CONFIG_MACH_TYPE	MACH_TYPE_MCX
 #define CONFIG_BOARD_LATE_INIT
 
+#define CONFIG_SYS_GENERIC_BOARD
+
 #define CONFIG_SYS_CACHELINE_SIZE	64
 
 #define CONFIG_EMIF4	/* The chip has EMIF4 controller */