iwlwifi: remove unneeded goto from iwl_dbgfs_log_event_read

Make code simpler a bit.

Reported-by: Jonas Gorski <jogo@openwrt.org>
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Reviewed-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>