builddeb: allow selection of .deb compressor

Select deb compression using KDEB_COMPRESS make variable. This allows to
use gzip compression for local or test builds, and that's way faster
than now-default xz compression.

Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

scripts/package/builddeb

@@ -43,7 +43,7 @@ create_package() {
 
 	# Create the package
 	dpkg-gencontrol -p$pname -P"$pdir"
-	dpkg --build "$pdir" ..
+	dpkg-deb ${KDEB_COMPRESS:+-Z$KDEB_COMPRESS} --build "$pdir" ..
 }
 
 version=$KERNELRELEASE