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 <hans-christian.egtvedt@atmel.com>
Signed-off-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>

arch/avr32/mach-at32ap/at32ap700x.c

@@ -1345,6 +1345,8 @@ at32_add_device_mci(unsigned int id, struct mci_platform_data *data)
 		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;
@@ -1357,7 +1359,7 @@ at32_add_device_mci(unsigned int id, struct mci_platform_data *data)
 
 	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;
@@ -1381,7 +1383,7 @@ at32_add_device_mci(unsigned int id, struct mci_platform_data *data)
 		/* Slot is unused */
 		break;
 	default:
-		goto fail;
+		goto fail_free;
 	}
 
 	select_peripheral(PIOA, pioa_mask, PERIPH_A, 0);
@@ -1408,7 +1410,7 @@ at32_add_device_mci(unsigned int id, struct mci_platform_data *data)
 		break;
 	default:
 		if (!data->slot[0].bus_width)
-			goto fail;
+			goto fail_free;
 
 		data->slot[1].bus_width = 0;
 		break;
@@ -1419,9 +1421,10 @@ at32_add_device_mci(unsigned int id, struct mci_platform_data *data)
 	platform_device_add(pdev);
 	return pdev;
 
+fail_free:
+	kfree(slave);
 fail:
 	data->dma_slave = NULL;
-	kfree(slave);
 	platform_device_put(pdev);
 	return NULL;
 }