sfc: Use CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS where appropriate

For some buffers we use a starting offset of either NET_IP_ALIGN or 0
depending on whether we believe the architecture supports efficient
access to unaligned words.  There is now a config macro specifying
whether this is the case, so check that rather than checking for
specific architectures.
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

drivers/net/sfc/net_driver.h

@@ -474,7 +474,7 @@ enum nic_state {
  * This is the equivalent of NET_IP_ALIGN [which controls the alignment
  * of the skb->head for hardware DMA].
  */
-#if defined(__i386__) || defined(__x86_64__)
+#ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
 #define EFX_PAGE_IP_ALIGN 0
 #else
 #define EFX_PAGE_IP_ALIGN NET_IP_ALIGN

drivers/net/sfc/tx.c

@@ -516,7 +516,7 @@ void efx_remove_tx_queue(struct efx_tx_queue *tx_queue)
 /* Number of bytes inserted at the start of a TSO header buffer,
  * similar to NET_IP_ALIGN.
  */
-#if defined(__i386__) || defined(__x86_64__)
+#ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
 #define TSOH_OFFSET	0
 #else
 #define TSOH_OFFSET	NET_IP_ALIGN