avr32: clean up memory allocation in at32_add_device_mci

This patch will check if the kzalloc for the MCI DMA struct actually
returns a valid address, and also clean up properly if it fails or the
function fails at a later stage.

This also silences a compiler warning about using the slave variable
uninitialized.

Signed-off-by: Hans-Christian Egtvedt <[e-mail]>
Signed-off-by: Haavard Skinnemoen <[e-mail]>

arch/avr32/mach-at32ap/at32ap700x.c

···
 		goto fail;
 
 	slave = kzalloc(sizeof(struct mci_dma_data), GFP_KERNEL);
+	if (!slave)
+		goto fail;
 
 	slave->sdata.dma_dev = &dw_dmac0_device.dev;
 	slave->sdata.reg_width = DW_DMA_SLAVE_WIDTH_32BIT;
···
 
 	if (platform_device_add_data(pdev, data,
 				sizeof(struct mci_platform_data)))
-		goto fail;
+		goto fail_free;
 
 	/* CLK line is common to both slots */
 	pioa_mask = 1 << 10;
···
 		/* Slot is unused */
 		break;
 	default:
-		goto fail;
+		goto fail_free;
 	}
 
 	select_peripheral(PIOA, pioa_mask, PERIPH_A, 0);
···
 		break;
 	default:
 		if (!data->slot[0].bus_width)
-			goto fail;
+			goto fail_free;
 
 		data->slot[1].bus_width = 0;
 		break;
···
 	platform_device_add(pdev);
 	return pdev;
 
+fail_free:
+	kfree(slave);
 fail:
 	data->dma_slave = NULL;
-	kfree(slave);
 	platform_device_put(pdev);
 	return NULL;
 }