drm/fourcc: Fill out all block sizes for P10/12/16

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: 05f8bc82 ("drm/fourcc: Add new P010, P016 video format")
Cc: Daniel Stone <daniel@fooishbar.org>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Randy Li <ayaka@soulik.info>
Cc: Clint Taylor <clinton.a.taylor@intel.com>
Cc: Ayan Kumar Halder <ayan.halder@arm.com>
Cc: Neil Armstrong <narmstrong@baylibre.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
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/20191126091414.226070-1-daniel.vetter@ffwll.ch