media: imx-jpeg: Fix potential error pointer dereference in detach_pm()

The proble is on the first line:

	if (jpeg->pd_dev[i] && !pm_runtime_suspended(jpeg->pd_dev[i]))

If jpeg->pd_dev[i] is an error pointer, then passing it to
pm_runtime_suspended() will lead to an Oops.  The other conditions
check for both error pointers and NULL, but it would be more clear to
use the IS_ERR_OR_NULL() check for that.

Fixes: fd0af4cd ("media: imx-jpeg: Ensure power suppliers be suspended before detach them")
Cc: <stable@vger.kernel.org>
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Ming Qian <ming.qian@nxp.com>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>