media: dvb: Add TSPP2 open/close device

TSPP2 driver updated API mandates opening TSPP2 device instance before
using further APIs and closing the device instance at teardown.
Instance is opened before the first TSPP2 source is initialized and
closed after the last source was terminated.
Reference count is used to verify instance is opened and closed only once.

Change-Id: Ia5cfb011e60f46d4b245845376e1373718c346fc
Signed-off-by: Gilad Broner <gbroner@codeaurora.org>