kbuild: deb-pkg: call more misc debhelper commands

Use dh_prep instead of removing old build directories manually.

Use dh_clean instead of removing build directories and debian/files
manually.

Call dh_testdir and dh_testroot for preliminary checks.

Signed-off-by: Masahiro Yamada <[e-mail]>
Reviewed-by: Nicolas Schier <[e-mail]>

scripts/package/builddeb

···
 	pname=$1
 	pdir=debian/$1
 
-	rm -rf ${pdir}
-
 	# Only some architectures with OF support have this target
 	if is_enabled CONFIG_OF_EARLY_FLATTREE && [ -d "${srctree}/arch/${SRCARCH}/boot/dts" ]; then
 		${MAKE} -f ${srctree}/Makefile INSTALL_DTBS_PATH="${pdir}/usr/lib/linux-image-${KERNELRELEASE}" dtbs_install
···
 install_linux_image_dbg () {
 	pdir=debian/$1
 
-	rm -rf ${pdir}
-
 	# Parse modules.order directly because 'make modules_install' may sign,
 	# compress modules, and then run unneeded depmod.
 	while read -r mod; do
···
 	pdir=debian/$1
 	version=${1#linux-headers-}
 
-	rm -rf $pdir
-
 	"${srctree}/scripts/package/install-extmod-build" "${pdir}/usr/src/linux-headers-${version}"
 
 	mkdir -p $pdir/lib/modules/$version/
···
 
 install_libc_headers () {
 	pdir=debian/$1
-
-	rm -rf $pdir
 
 	$MAKE -f $srctree/Makefile headers_install INSTALL_HDR_PATH=$pdir/usr
 

scripts/package/debian/rules

···
 DH_OPTIONS = -p$(package)
 
 define binary
+	$(Q)dh_testdir $(DH_OPTIONS)
+	$(Q)dh_testroot $(DH_OPTIONS)
+	$(Q)dh_prep $(DH_OPTIONS)
 	$(Q)+$(MAKE) $(make-opts) run-command KBUILD_RUN_COMMAND='+$$(srctree)/scripts/package/builddeb $(package)'
 	$(Q)dh_installdocs $(DH_OPTIONS)
 	$(Q)dh_installchangelogs $(DH_OPTIONS)
···
 
 .PHONY: clean
 clean:
-	$(Q)rm -rf debian/files debian/linux-* debian/deb-env.vars* debian/*.files
+	$(Q)dh_clean
+	$(Q)rm -rf debian/deb-env.vars* debian/*.files
 	$(Q)$(MAKE) ARCH=$(ARCH) clean
 
 # If DEB_HOST_ARCH is empty, it is likely that debian/rules was executed