PNPACPI: Fix device ref leaking in acpi_pnp_match

During testing pci root bus removal, found some root bus bridge is not freed.
If booting with pnpacpi=off, those hostbridge could be freed without problem.
It turns out that some devices reference are not released during acpi_pnp_match.
that match should not hold one device ref during every calling.
Add pu_device calling before returning.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: stable@vger.kernel.org
Signed-off-by: Len Brown <len.brown@intel.com>