drm/fourcc: Fill out all block sizes for P210

0 means 1 as the default, but it's mighty confusing if the block size
for the first plane is spelled out explicitly, but not for the 2nd
plane.

No cc: stable because this is just confusion, but 0 functional issue.

Acked-by: Liviu Dudau <liviu.dudau@arm.com>
Fixes: 7ba0fee2 ("drm/fourcc: Add AFBC yuv fourccs for Mali")
Cc: Brian Starkey <brian.starkey@arm.com>
Cc: Ayan Kumar Halder <ayan.halder@arm.com>
Cc: Liviu Dudau <liviu.dudau@arm.com>
Cc: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191126091414.226070-2-daniel.vetter@ffwll.ch