iwlwifi: mvm: fix bug with OTP memory size

OTP size changed in family 7000 and in family 8000.

Signed-off-by: Eran Harary <eran.harary@intel.com>
Reviewed-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>