[media] s5p-mfc: Add NULL check for allocated buffer

In certain cases, dma_alloc_coherent returns NULL. Add check for
NULL pointer.
Signed-off-by: NSachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: NKamil Debski <k.debski@samsung.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/platform/s5p-mfc/s5p_mfc_ctrl.c

@@ -38,7 +38,7 @@ int s5p_mfc_alloc_firmware(struct s5p_mfc_dev *dev)
 	dev->fw_virt_addr = dma_alloc_coherent(dev->mem_dev_l, dev->fw_size,
 					&dev->bank1, GFP_KERNEL);
 
-	if (IS_ERR(dev->fw_virt_addr)) {
+	if (IS_ERR_OR_NULL(dev->fw_virt_addr)) {
 		dev->fw_virt_addr = NULL;
 		mfc_err("Allocating bitprocessor buffer failed\n");
 		return -ENOMEM;