msm: synx: Reuse the released synx handles

Reuse the synx handles released by removing them
from the idr rather than just invalidating them
for future usage as it might result in resource
exhaustion from unavailability of new handles.

Change-Id: I26a7ba3874f8d6c878c8d3c2739914a1d142114e
Signed-off-by: Sumukh Hallymysore Ravindra <shallymy@codeaurora.org>