php::cgi: Fix deprecate variable notation in inline template

```puppet
Debug: template[inline]: Bound template variables for inline template in 0.00 seconds
Warning: Variable access via 'upload_max_files' is deprecated. Use '@upload_max_files' instead. template[inline]:2
   (at /usr/lib/ruby/vendor_ruby/puppet/parser/templatewrapper.rb:76:in `method_missing')
Debug: template[inline]: Interpolated template inline template in 0.00 seconds
```