Wire the shared Ameba ADC driver into the RTL8720F build: add the
per-chip ameba_adc_chip.h (9 channels, CH0..CH5 external on
PA13..PA18, PINMUX function 5, APB clock on bit24), the board ADC
table and registration, the adc board config, and build glue for
both cmake and make (including the fwlib RAM-layer ameba_adc.c in
ameba_board.mk). Document the ADC on the board index.
Signed-off-by: dechao_gong <dechao_gong@realsil.com.cn>
Assisted-by: Claude <noreply@anthropic.com>