How do I disable the touchpad using the upper left corner on an HP Pavilion dv6?

The option you mentoined is a driver feature - there is no linux alternative for that until someone do patch for it.

Look around touchpad settings and you'll find useful replacement settings. For example you can set up a keyboard shourtcut to turn on/off touchpad.

gsettings set org.gnome.settings-daemon.peripherals.touchpad disable-while-typing true 

will disable your touchpad while you are typing and re-enable it when it feels that you are using your finger on the touchpad.

Not sure if it will fit your needs but its a solution that fits me perfectly on my laptop.

To revert to the default parameter use

gsettings set org.gnome.settings-daemon.peripherals.touchpad disable-while-typing false

If it doesn't help drop a comment, well figure out something about your touchpad.