boards: nordic: nrf54lm20dk: remove support for wdt from flpr

Should not be added in first place, never working.

Signed-off-by: Piotr Kosycarz <[email protected]>

Author: nordic-piks

boards/nordic/nrf54lm20dk/nrf54lm20dk_nrf54lm20a_cpuflpr.yaml

@@ -13,4 +13,3 @@ flash: 96
 supported:
   - counter
   - gpio
-  - watchdog