dmaengine: tegra: add tracepoints to driver

Add some trace-points to the driver to allow for debuging via the
trace pipe.

Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Vinod Koul <vkoul@kernel.org>