CSIT-1046 Make uio driver configurable from topofiles

Currently we are configuring uio_driver from global variable.
This may not be suitable for various topologies where we need
different driver per TB. This patch is suppose to put uio_driver
into topology files.

Change-Id: I56af0697e8b2359ccb126151217976408720c1ba
Signed-off-by: Peter Mikus <pmikus@cisco.com>