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

Also, create a gio_bus_release() that calls kfree on the device argument to
properly kfree() the memory allocated for the device.

[ralf@linux-mips.org: Reformat to Linux coding style and make
gio_bus_release static.]
Signed-off-by: Levente Kurusa <levex@linux.com>
Cc: LKML <linux-kernel@vger.kernel.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6261/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>