V4L/DVB (9602): dvb-ttusb-budget: Add NULL pointer validation

Added validation for NULL pointer

Signed-off-by: Douglas Schilling Landgraf <[e-mail]>
Signed-off-by: Mauro Carvalho Chehab <[e-mail]>

drivers/media/dvb/ttusb-budget/dvb-ttusb-budget.c

···
 						 ISO_BUF_COUNT,
 						 &ttusb->iso_dma_handle);
 
+	if (!ttusb->iso_buffer) {
+		dprintk("%s: pci_alloc_consistent - not enough memory\n",
+			__func__);
+		return -ENOMEM;
+	}
+
 	memset(ttusb->iso_buffer, 0,
 	       ISO_FRAME_SIZE * FRAMES_PER_ISO_BUF * ISO_BUF_COUNT);