media: media/platform: don't set description in ENUM_FMT

The V4L2 core sets the format description and flags for the driver in order
to ensure consistent naming.

So drop the strscpy of the description in drivers. Also remove any
description strings in driver-internal structures since those are
no longer needed.

And in am437x-vpfe.c drop an unnecessary f->type assignment in
vpfe_enum_fmt().

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Acked-by: Benoit Parrot <bparrot@ti.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
[hverkuil-cisco@xs4all.nl: addressed some small suggestions from Laurent]
Acked-by: Lad, Prabhakar <prabhakar.csengg@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>