p54: drop device reference count if fails to enable device

commit 8149069d upstream.

The function p54p_probe takes an extra reference count of the PCI
device. However, the extra reference count is not dropped when it fails
to enable the PCI device. This patch fixes the bug.

Signed-off-by: Pan Bian <bianpan2016@163.com>
Acked-by: Christian Lamparter <chunkeey@gmail.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
[bwh: Backported to 3.16: adjust filename]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>