media: v4l2-jpeg: ignore the unknown APP14 marker

The legal identifier of APP14 is "Adobe\0",
but sometimes it may be
"This is an unknown APP marker . Compliant decoders must ignore it."
In this case, just ignore it.
It won't affect the decode result.

Fixes: b8035f79 ("media: Add parsing for APP14 data segment in jpeg helpers")
Signed-off-by: Ming Qian <ming.qian@nxp.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>