kbuild: deb-pkg: fix binary-arch and clean in debian/rules

The clean target needs ARCH=${ARCH} to clean up the tree for the correct
architecture. 'make (bin)deb-pkg' skips cleaning, but the preclean hook
may be executed if dpkg-buildpackage is directly used.

The binary-arch target does not need KERNELRELEASE because it is not
updated during the installation. KBUILD_BUILD_VERSION is not needed
either because binary-arch does not build vmlinux.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>