configs/minnowboard_max-graphical: wchar/grub2 fix
minnowboard_max-graphical_defconfig has the line "BR_TARGET_GRUB2=y",
but this currently has no effect because BR_TARGET_GRUB2 cannot be
selected without BR2_TOOLCHAIN_BUILDROOT_WCHAR=y, which is not set by
default.
The minnowboard max defconfig was updated to fix this problem, but the
graphical variant was not updated alongside it.
Signed-off-by: Nicholas Sielicki <sielicki@yandex.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>