Revert "Remove unnecessary return"

This reverts commit 843d2506e1a1eab17b871bc38b204d27047c9ff7.
diff --git a/system/database/drivers/mysql/mysql_driver.php b/system/database/drivers/mysql/mysql_driver.php
index d571c45..f8e9b6d 100644
--- a/system/database/drivers/mysql/mysql_driver.php
+++ b/system/database/drivers/mysql/mysql_driver.php
@@ -390,7 +390,7 @@
 
 		if ($prefix_limit !== FALSE && $this->dbprefix !== '')
 		{
-			$sql ." LIKE '".$this->escape_like_str($this->dbprefix)."%'";
+			return $sql." LIKE '".$this->escape_like_str($this->dbprefix)."%'";
 		}
 
 		return $sql;