For filters based on framesync, the input frame was managed
by framesync, so we should not directly keep and destroy it,
instead we make a clone of it here, or else double-free will occur.
But for other filters not based on framesync, we still need to
free the input frame inside filter_frame.
Signed-off-by: Ruiling Song <ruiling.song@intel.com>
(cherry picked from commit d865783b)