media: imx-jpeg: Clear slot next desc ptr if config error

clear slot next desc ptr if config error,
otherwise codec will report config error interrupt repeatedly,
it may led to system hang.

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>