adv7481: Update adv7481 because of v4l2 changes

Make use of the new media_bus_format definitions;
Replace video op g_mbus_fmt/s_mbus_fmt by pad op get_fmt/set_fmt

Change-Id: I2e52c81d2672c4773ea4adccd3cc50d5926bd65f
Signed-off-by: Jingtao Chen <jingtaoc@codeaurora.org>