AM33XX: etamin: remove CONFIG_DFU_MTD

This macro is defined, but not referenced by anyone.

I did not touch config_whitelist.txt - the CONFIG will be dropped
by the next re-sync.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>

include/configs/etamin.h

@@ -120,7 +120,6 @@
 
 
 
-#define CONFIG_DFU_MTD
 #undef COMMON_ENV_DFU_ARGS
 #define COMMON_ENV_DFU_ARGS	"dfu_args=run bootargs_defaults;" \
 				"setenv bootargs ${bootargs};" \