[media] dib8000: Fix handling of interleave bigger than 2

If interleave is bigger than 2, the code will set it to 0, as
dib8000 registers use a log2(). So, change the code to handle
it accordingly.

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