ata: fix acpi_bus_get_device() return value check

Since acpi_bus_get_device() returns plain int and not acpi_status,
ACPI_FAILURE() should not be used for checking its return value.  Fix
that.

tj: Dropped unused local variable @status from odd_can_poweroff().
    Reported by kbuild test bot.

Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Aaron Lu <aaron.lu@intel.com>
Cc: linux-ide@vger.kernel.org
Cc: kbuild test robot <fengguang.wu@intel.com>