usb: musb: ux500_dma: fix potential NULL dereference error

static checker warning: "drivers/usb/musb/ux500_dma.c:335
ux500_dma_controller_start()
         error: potential NULL dereference 'param_array'."

Acked-by: Linus Walleij <linus.walleij@linaro.org>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/musb/ux500_dma.c

@@ -336,7 +336,9 @@ static int ux500_dma_controller_start(struct ux500_dma_controller *controller)
 							    data ?
 							    data->dma_filter :
 							    NULL,
-							    param_array[ch_num]);
+							    param_array ?
+							    param_array[ch_num] :
+							    NULL);
 
 			if (!ux500_channel->dma_chan) {
 				ERR("Dma pipe allocation error dir=%d ch=%d\n",