The land given for path way for all users shall be termed as public way only and not anyone's individual property.
A single person cannot claim ownership to such property which comprises properties belonging to different owners.
The foot path or any definition given to this property that has been donated by you along with your neighbor was for the purpose of common way for the users, if it does not serve the purpose then there is no use of donating that piece of land by you which has been mentioned in the deed. Moreover your neighbor has no authority to occupy the property which does not belong to him and is allotted for the common cause.
Ask him to prove the title to the property which he is illegally occupying now without any authority.
You can very well defend yourself by mentioning the same what has been mentioned in your title deed about the portion of property allotted for the common cause.