kbuild: deb-pkg: set version for linux-headers paths

As a result of the switch to dh_listpackages, $version is no longer set
when install_kernel_headers() is called.  This causes files in the
linux-headers deb package to be installed to a path with an empty
$version (e.g. /usr/src/linux-headers-/scripts/sign-file rather than
/usr/src/linux-headers-6.3.0-rc3/scripts/sign-file).

To avoid this, while continuing to use the version information from
dh_listpackages, pass $version from $package as the second argument
of install_kernel_headers().

Fixes: 36862e14

 ("kbuild: deb-pkg: use dh_listpackages to know enabled packages")
Signed-off-by: Kevin Locke <kevin@kevinlocke.name>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>