x86/vdso: Remove x32 intermediates during 'make clean'

The existing clean-files rule was missing vdsox32.so and
vdsox32.so.dbg.  We should really rename the intermediates to
allow a single rule to get them all.

Also-reported-by: Magnus Damm <damm+renesas@opensource.se>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Link: http://lkml.kernel.org/r/7fa2ad4a63bc6f52e214125900d54165ef06cc10.1427482099.git.luto@kernel.org


Signed-off-by: Ingo Molnar <mingo@kernel.org>