drm: vc4: Omit pixel_order from the hvs_format for hvs5 only formats

pixel_order is used for the earlier versions of the HVS, so is
redundant on the 10:10:10:2 and 10bit YUV formats that are only
supported on HVS5.
Remove the assignment from the table to avoid confusion.

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