minnowboard_max_defconfig: grub2 needs WCHAR

Since commit 5ffafd2353f5d67 (grub2: bump up version), grub2 needs a
toolchain with WCHAR support. However, the defconfigs that use grub2
were not updated at the time.

Add BR2_TOOLCHAIN_BUILDROOT_WCHAR=y to minnowboard_max_defconfig.

Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Cc: Erico Nunes <nunes.erico@gmail.com>
Cc: Peter Korsgaard <peter@korsgaard.com>
Cc: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>
Cc: Vincent Stehlé <vincent.stehle@intel.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

configs/minnowboard_max_defconfig

@@ -9,6 +9,9 @@ BR2_ROOTFS_POST_IMAGE_SCRIPT="board/minnowboard/post-image.sh"
 
 # Linux headers same as kernel, a 4.12 series
 BR2_PACKAGE_HOST_LINUX_HEADERS_CUSTOM_4_12=y
+# Needed for grub2
+BR2_TOOLCHAIN_BUILDROOT_WCHAR=y
+
 BR2_PACKAGE_HOST_DOSFSTOOLS=y
 BR2_PACKAGE_HOST_GENIMAGE=y
 BR2_PACKAGE_HOST_MTOOLS=y