Is there a way I can put a link in my mobile website, clicking on which - the user gets directed to the Uber App, with the drop location parameter already there?
Yes, this is possible. Check out the deeplink resource here: https://developer.uber.com/docs/riders/ride-requests/tutorials/deep-links/introduction
"The setPickup action is a very powerful deep linking feature which allows you to launch the Uber app and do any combination of setting pickup, drop-off, and product selection."