wifi: iwlwifi: mvm: make pldr_sync AX210 specific

The register here is device specific, so we need to gate
the reading/checking to apply only on AX210 family.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://lore.kernel.org/r/20230921110726.928901700ad8.I648efdc4400d9e537359915a9a8f363d5d255ead@changeid


Signed-off-by: Johannes Berg <johannes.berg@intel.com>