samples: zephyr: drivers: counter: alarm: Disable on nrf54lm20pdk

Original sample in the Zephyr repository is now executed on
final board name of nrf54lm20dk/nrf54lm20a/cpuapp.

Disable execution on obsolete nrf54lm20pdk target.

Signed-off-by: Sebastian Głąb <[email protected]>

Author: nordic-segl

samples/zephyr/drivers/counter/alarm/boards/nrf54lm20pdk_nrf54lm20a_cpuapp.overlay

@@ -22,15 +22,10 @@ tests:
     platform_allow:
       - nrf54h20dk/nrf54h20/cpuapp
       - nrf54l15dk/nrf54l15/cpuapp
-      - nrf54lm20pdk/nrf54lm20a/cpuapp
-      - [email protected]/nrf54lm20a/cpuapp
-      - [email protected]/nrf54lm20a/cpuapp
-      - [email protected]/nrf54lm20a/cpuapp
       - nrf54lv10dk/nrf54lv10a/cpuapp
       - [email protected]/nrf54lv10a/cpuapp
       - [email protected]/nrf54lv10a/cpuapp
     integration_platforms:
       - nrf54h20dk/nrf54h20/cpuapp
       - nrf54l15dk/nrf54l15/cpuapp
-      - nrf54lm20pdk/nrf54lm20a/cpuapp
       - nrf54lv10dk/nrf54lv10a/cpuapp