ACPI: video - add missing input_free_device()

If input_register_device() fails input_free_device() must
be called to release memory allocated for the device.
Also consolidate error handling in acpi_bus_video_add()
and handle input_allocate_device() failures.

Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
Acked-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>