DaVinci: EDMA: Fix Bug while obtaining contiguous params

The reserve_contiguous_params function is used to reserve
a set of contiguous PARAMs. If we do not find a complete
set of contiguous PARAMs, the functions still has to free
every PARAM that it found to be free in the process of finding a
complete set and thus marked as "in use".
This patch mainly deals with correctly handling the
freeing of PARAMs.

Signed-off-by: Sandeep Paulraj <s-paulraj@ti.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>