[media] dib8000: add DVBv5 stats

The advantage of DVBv5 stats is that it allows adding proper
scales to all measures. use it for this frontend.

This patch adds a basic set of stats, basically cloning what's already
provided by DVBv3 API. Latter patches will improve it.

Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
Acked-by: Patrick Boettcher <pboettcher@kernellabs.com>