drm/vc4: FKMS Block modes with odd horizontal timing values on Pi4

Pi4 HDMI pipeline is 2 pixels/clock and can not produce timings
that have odd values for active pixels, front porch, sync width,
or back porch.
Detect these modes and block them within fkms.

Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>