media: imx-jpeg: Fix possible null pointer dereference

Found by Coverity scan.
Signed-off-by: Mirela Rabulea <mirela.rabulea@nxp.com>
Reviewed-by: Laurentiu Palcu <laurentiu.palcu@nxp.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

drivers/media/platform/imx-jpeg/mxc-jpeg.c

@@ -575,6 +575,10 @@ static irqreturn_t mxc_jpeg_dec_irq(int irq, void *priv)
 
 	dst_buf = v4l2_m2m_next_dst_buf(ctx->fh.m2m_ctx);
 	src_buf = v4l2_m2m_next_src_buf(ctx->fh.m2m_ctx);
+	if (!dst_buf || !src_buf) {
+		dev_err(dev, "No source or destination buffer.\n");
+		goto job_unlock;
+	}
 	jpeg_src_buf = vb2_to_mxc_buf(&src_buf->vb2_buf);
 
 	if (dec_ret & SLOT_STATUS_ENC_CONFIG_ERR) {