ibmvnic: fix dma_mapping_error call

This patch fixes the dma_mapping_error call to use the correct dma_addr
which is inside the ibmvnic_vpd struct. Moreover, it fixes an uninitialized
warning regarding a local dma_addr variable which is not used anymore.

Fixes: 4e6759be ("ibmvnic: Feature implementation of VPD for the ibmvnic driver")
Reported-by: NStephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NDesnes A. Nunes do Rosario <desnesn@linux.vnet.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/ibm/ibmvnic.c

@@ -849,7 +849,6 @@ static int ibmvnic_get_vpd(struct ibmvnic_adapter *adapter)
 {
 	struct device *dev = &adapter->vdev->dev;
 	union ibmvnic_crq crq;
-	dma_addr_t dma_addr;
 	int len = 0;
 
 	if (adapter->vpd->buff)
@@ -879,7 +878,7 @@ static int ibmvnic_get_vpd(struct ibmvnic_adapter *adapter)
 	adapter->vpd->dma_addr =
 		dma_map_single(dev, adapter->vpd->buff, adapter->vpd->len,
 			       DMA_FROM_DEVICE);
-	if (dma_mapping_error(dev, dma_addr)) {
+	if (dma_mapping_error(dev, adapter->vpd->dma_addr)) {
 		dev_err(dev, "Could not map VPD buffer\n");
 		kfree(adapter->vpd->buff);
 		return -ENOMEM;