media: nxp: Fix wrong return pointer check in mxc_isi_crossbar_init()

It should check 'xbar->inputs', when allocate memory for it.

Cc: stable@vger.kernel.org
Fixes: cf21f328 ("media: nxp: Add i.MX8 ISI driver")
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Reviewed-by: Fabio Estevam <festevam@gmail.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>