kbuild: deb-pkg: remove the fakeroot builds support

In 2017, the dpkg suite introduced the rootless builds support with the
following commits:

  - 2436807c87b0 ("dpkg-deb: Add support for rootless builds")
  - fca1bfe84068 ("dpkg-buildpackage: Add support for rootless builds")

This feature is available in the default dpkg on Debian 10 and Ubuntu
20.04.

Remove the old method.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

scripts/Makefile.package

@@ -109,8 +109,6 @@ debian-orig: linux.tar$(debian-orig-suffix) debian
 		cp $< ../$(orig-name); \
 	fi
 
-KBUILD_PKG_ROOTCMD ?= 'fakeroot -u'
-
 PHONY += deb-pkg srcdeb-pkg bindeb-pkg
 
 deb-pkg:    private build-type := source,binary
@@ -125,7 +123,7 @@ deb-pkg srcdeb-pkg bindeb-pkg:
 	$(if $(findstring source, $(build-type)), \
 		--unsigned-source --compression=$(KDEB_SOURCE_COMPRESS)) \
 	$(if $(findstring binary, $(build-type)), \
-		-R'$(MAKE) -f debian/rules' -j1 -r$(KBUILD_PKG_ROOTCMD) -a$$(cat debian/arch), \
+		-R'$(MAKE) -f debian/rules' -j1 -a$$(cat debian/arch), \
 		--no-check-builddeps) \
 	$(DPKG_FLAGS))
 

scripts/package/builddeb

@@ -36,19 +36,13 @@ create_package() {
 	sh -c "cd '$pdir'; find . -type f ! -path './DEBIAN/*' -printf '%P\0' \
 		| xargs -r0 md5sum > DEBIAN/md5sums"
 
-	# Fix ownership and permissions
-	if [ "$DEB_RULES_REQUIRES_ROOT" = "no" ]; then
-		dpkg_deb_opts="--root-owner-group"
-	else
-		chown -R root:root "$pdir"
-	fi
 	# a+rX in case we are in a restrictive umask environment like 0077
 	# ug-s in case we build in a setuid/setgid directory
 	chmod -R go-w,a+rX,ug-s "$pdir"
 
 	# Create the package
 	dpkg-gencontrol -p$pname -P"$pdir"
-	dpkg-deb $dpkg_deb_opts ${KDEB_COMPRESS:+-Z$KDEB_COMPRESS} --build "$pdir" ..
+	dpkg-deb --root-owner-group ${KDEB_COMPRESS:+-Z$KDEB_COMPRESS} --build "$pdir" ..
 }
 
 install_linux_image () {