Despite the struct says "color16", it was actually using 32 bits
for each color. Fix it.
Suggested-by: NHans Verkuil <hverkuil@xs4all.nl>
Acked-by: NHans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@s-opensource.com>