Normally PDO mysql extension will be enabled once you installed it through Easyapache. However, in cPanel 11.32 versions, if you are seeing PDO_mysql extension is not enabled after easyapache, then you need to install the PDO_mysql extension from PECL repository.
#pecl install PDO_MYSQL
After installing, check the installed modules using the following command.
#pecl list PDO PDO support => enabled PDO drivers => mysql pdo_mysql PDO Driver for MySQL, client library version => 5.0.95
