boards: quark_d2000_crb: Remove adc support

Remove ADC support from d2000 as it is not migrated to
new ADC apis.

Signed-off-by: Punit Vara <[email protected]>

Author: punitvara

boards/x86/quark_d2000_crb/quark_d2000_crb.yaml

@@ -9,7 +9,6 @@ toolchain:
 ram: 8
 flash: 32
 supported:
-  - adc
   - i2c
   - spi
   - gpio