media: v4l2-ctrls: Fix missing newline in examples

Replace supportedn with supported\n , i.e. add the missing backslash.

Signed-off-by: Marek Vasut <marex@denx.de>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>