samples: zephyr: drivers: spi_bitbang: Disable on official nrf54*

Original sample in the Zephyr repository is now executed on
- nrf54h20dk/nrf54h20/cpuapp,
- nrf54l15dk/nrf54l15/cpuapp,
- nrf54lm20dk/nrf54lm20a/cpuapp.

Disable duplicated targets.

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

Author: nordic-segl

samples/zephyr/drivers/spi_bitbang/boards/nrf54h20dk_nrf54h20_cpuapp.overlay

@@ -8,12 +8,6 @@ tests:
       - gpio
       - ci_samples_zephyr_drivers_spi_bitbang
     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