wifi: iwlwifi: tests: check for duplicate name strings

We don't need the same name multiple times in the binary,
add a check for that.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Link: https://patch.msgid.link/20250502155404.9adf2790122e.Ia85152c072c7944f0b80e819cf59a51d6adeb49a@changeid