tools: fix typo in tools/image-host.c

fix a typo in error printf. If FIT_CONFS_PATH is not found
print FIT_CONFS_PATH not FIT_IMAGES_PATH.

Signed-off-by: Heiko Schocher <hs@denx.de>
Cc: Simon Glass <sjg@chromium.org>
Acked-by: Simon Glass <sjg@chromium.org>