media: pixfmt-yuv-planar.rst: fix PDF OUTPUT

Add missing format macros for the tables there to be properly
output.

While here, also remove the empty ".. note::" markup.

It should be noticed that ".. [1]" markups will generate footnotes,
and not a note within the main text body.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>