[nrf noup] dts: nordic: Support disabling lfosc

nrf-squash! [nrf noup] dts: nordic: Add support for BICR generation

The BICR LFOSC.LFXOCONFIG.MODE field supports disabling the usage of an
external crystal oscillator to disable LFXO as LF clock source. This
adds the enum to the binding, the rest of the codebase already supports
the feature.

Signed-off-by: Karsten Koenig <[email protected]>

Author: karstenkoenig

dts/bindings/misc/nordic,nrf-bicr.yaml

@@ -76,6 +76,7 @@ properties:
       - "crystal"
       - "external-sine"
       - "external-square"
+      - "disabled"
 
   lfosc-loadcap:
     type: int