Remove mtdev dependency from the touchscreen QPA plugin.

Remove mtdev dependency from the touchscreen QPA plugin.

There is no reason to enforce the usage of the mtdev library. As long
as ABS_MT_TRACKING_ID is provided protocol type A is perfectly enough.

This makes the plugin more suitable for embedded systems.

Change-Id: I73ce4a1056a6dc27daacb69dc4761bca393a7e43
Reviewed-by: Paul Olav Tvete <paul.tvete@nokia.com>