Build errors if CONFIG_SONY_LAPTOP && !INPUT or
if CONFIG_THINKPAD_ACPI && !INPUT:

 LD      vmlinux
    ...
drivers/built-in.o: In function `sony_laptop_remove_input':
sony-laptop.c:(.text+0x768fb): undefined reference to `input_unregister_device'
    ...
drivers/built-in.o: In function `thinkpad_acpi_module_exit':
thinkpad_acpi.c:(.text+0x78c1b): undefined reference to `input_free_device'
    ...
Signed-off-by: NAndreas Herrmann <aherrman@arcor.de>
Acked-by: NHenrique de Moraes Holschuh <hmh@hmh.eng.br>
Acked-by: NMattia Dongili <malattia@linux.it>
Signed-off-by: NLen Brown <len.brown@intel.com>