drm/vc4: Fix setting of vertical timings in the CRTC.

It looks like when I went to add the interlaced bits, I just took the
existing PV_VERT* block and indented it, instead of copy and pasting
it first.  Without this, changing resolution never worked.

Signed-off-by: Eric Anholt <eric@anholt.net>
(cherry picked from commit a7c5047d)