x86: fix duplicate free in setup_pcpu_remap() failure path

In the failure path, setup_pcpu_remap() tries to free the area which
has already been freed to make holes in the large page.  Fix it.

[ Impact: fix duplicate free in failure path ]

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Ingo Molnar <mingo@elte.hu>