Remove unused arguments in function statistics_recent_hits()

Function statistics_recent_hits() defines 2 arguments that are not used.

This:

function statistics_recent_hits($type = 'all', $id = 0) {

Should look like:

function statistics_recent_hits() {

I have previously reported a couple of issues related to the statistics module:
http://drupal.org/node/47989
http://drupal.org/node/47426

...if patches applied, line numbers for this one wouldn't match.