iwlwifi: remove EEPROM version message by default

If the EEPROM reading was successful, don't print
a message by default, the EEPROM version isn't all
that interesting. Change the message to DEBUG_INFO
priority so it can still be obtained.

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