MIPS: TXx9: Add missing put_device call

MIPS: TXx9: Add missing put_device call

This is required so that we give up the last reference to the device.

Also, rework error path so that it is easier to read.

[ralf@linux-mips.org: Reformat to Linux coding style and make
txx9_device_release static; folded in build fix by Levente for the
original patch.]

Signed-off-by: Levente Kurusa <levex@linux.com>
Cc: LKML <linux-kernel@vger.kernel.org>
Cc: Aaro Koskinen <aaro.koskinen@iki.fi>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Cc: Steven J. Hill <Steven.Hill@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6259/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>