ACPI: thinkpad-acpi: fix selects in Kconfig

Add missing select for BACKLIGHT_LCD_SUPPORT, as select doesn't select the
dependencies of a symbol for us.

Also, "select INPUT" in Kconfig.  We are not an Input device, nor are we
anywhere close to the input subsystem in the Kconfig tree, so using
"depends on INPUT" is not user-friendly at all.

Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Signed-off-by: Len Brown <len.brown@intel.com>