compliance: extend image exclusions in the checker

The checker still checked images that were deeper
in the path. Extending the exclusion.

Ref: nrfconnect#10772

Signed-off-by: Pekka Niskanen <pekka.niskanen@nordicsemi.no>

Author: peknis

.checkpatch.conf

@@ -42,5 +42,7 @@
 --exclude doc/nrf/images
 --exclude doc/nrf/.*/images
 --exclude doc/nrf/.*/.*/images
+--exclude doc/nrf/.*/.*/.*/images
+--exclude doc/nrf/.*/.*/.*/.*/images
 --exclude applications/nrf5340_audio/src/utils/macros
 --exclude lib/bin/lwm2m_carrier/include