V4L/DVB: V4L: tvp514x: Add Powerup sequence during s_input to lock the signal properly
For the sequence streamon -> streamoff and again s_input, it fails
to lock the signal, since streamoff puts TVP514x into power off state
which leads to failure in sub-sequent s_input.
So add powerup sequence in s_routing (if disabled), since it is
important to lock the signal at this stage.