
The BUTTON_ADC symbol guards the compilation of button-adc driver whose name very well makes it explicit that it requires ADC support to be enabled. Fix build issue of button-adc driver when ADC support isn't enabled by making sure it cannot be built without ADC support. Cc: Quentin Schulz <foss+uboot@0leil.net> Reviewed-by: Kever Yang <kever.yang@rock-chips.com> Signed-off-by: Quentin Schulz <quentin.schulz@theobroma-systems.com>