i7core_edac: Fix the logic in i7core_remove()

commit 47251b4d960bdfa648b0d06dbc6d445f41cb3906 have changed
the logic for unexplained reasons.  It looks strange that it
can release i7core_dev without calling i7core_put_devices()
that releases i7core_dev->pdev.

Fix the part.

Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>