vpp: Make sure element is deinit'ed properly.
vpp: Make sure element is deinit'ed properly.

Set ports, component, and factory to NULL after they were
unreferenced on the dispose method. Move omx_stop method from
READY_TO_NULL state transition to PAUSED_TO_READY.

Signed-off-by: Daniel Diaz <ed054987dd20aebbd314fbb0d175066628f13717@ti.com>

mrchapp/gst-goo,mrchapp/gst-goo