buildscript: Indicate current patch being applied

So far, we only saw the files affected, but not the patch used.

Signed-off-by: Adrian Schmutzler <freifunk@adrianschmutzler.de>
Reviewed-by: Christian Dresel <fff@chrisi01.de>

buildscript

@@ -125,6 +125,7 @@ get_source() {
 patch_target() {
     if [ "$(find "$PWD"/build_patches/openwrt/*.patch 2> /dev/null | wc -l)" -ge 1 ]; then
         for patch in "$PWD"/build_patches/openwrt/*.patch; do
+            echo "Applying $patch:"
             patch --no-backup-if-mismatch -p1 -d "$target" -i "$patch"
         done
     fi