buildscript: Fix typo

Signed-off-by: Adrian Schmutzler <freifunk@adrianschmutzler.de>
Reviewed-by: Fabian Bläse <fabian@blaese.de>
Reviewed-by: Tim Niemeyer <tim@tn-x.org>

buildscript

@@ -287,7 +287,7 @@ cp_firmware() {
             if [[ -f "$target/bin/targets/${chipset}/generic/$image_factory" ]]; then
               filename_build_factory=${filename_build/sysupgrade/factory$region}
               if [ ${#image_factory} -lt ${#filename_build_factory} ]; then
-                echo "Warning: The factory image file name (${filename_build_factory}) is longer than the OpenWrt one, which might be incompatibility with the stock firmware."
+                echo "Warning: The factory image file name (${filename_build_factory}) is longer than the OpenWrt one, which might lead to incompatibility with the stock firmware."
               fi
               cp "$target/bin/targets/${chipset}/generic/$image_factory" "./bin/$filename_build_factory"
             fi