iwlwifi: fix syslog message for event log dump size

When trigger event log dumping from debugfs, the entire event log
should be dumped and the size should match the number of events being
dump.

Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>