configs/orangepipc: add host-dosfstools

genimage from the post-image script needs mkdosfs to create fat partition:

>>>   Executing post-image script board/orangepi/orangepipc/post-image.sh
sh: 1: mkdosfs: not found
vfat(boot.vfat): failed to generate boot.vfat

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

configs/orangepipc_defconfig

@@ -27,5 +27,6 @@ BR2_TARGET_UBOOT_CUSTOM_REPO_VERSION="4832e17787acb29734d895751bc7a594908aecc6"
 BR2_TARGET_UBOOT_NEEDS_DTC=y
 BR2_TARGET_UBOOT_FORMAT_CUSTOM=y
 BR2_TARGET_UBOOT_FORMAT_CUSTOM_NAME="u-boot-sunxi-with-spl.bin"
+BR2_PACKAGE_HOST_DOSFSTOOLS=y
 BR2_PACKAGE_HOST_GENIMAGE=y
 BR2_PACKAGE_HOST_UBOOT_TOOLS=y