Since commit 27cb7300ff ("Ensure device tree DTS is compiled"),
build succeeds irrespective of the correctness of Makefile.
I am going to revert that commit, so wrong code must be fixed.
CONFIG_MCR3000 is not defined anywhere. CONFIG_TARGET_MCR3000 is the
correct one.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>