xtensa: nommu support

Add support for !CONFIG_MMU setups.

Signed-off-by: Johannes Weiner <jw@emlix.com>
Signed-off-by: Chris Zankel <chris@zankel.net>
diff --git a/arch/xtensa/include/asm/dma.h b/arch/xtensa/include/asm/dma.h
index e30f3ab..137ca39 100644
--- a/arch/xtensa/include/asm/dma.h
+++ b/arch/xtensa/include/asm/dma.h
@@ -44,8 +44,9 @@
  *	the value desired).
  */
 
+#ifndef MAX_DMA_ADDRESS
 #define MAX_DMA_ADDRESS		(PAGE_OFFSET + XCHAL_KIO_SIZE - 1)
-
+#endif
 
 /* Reserve and release a DMA channel */
 extern int request_dma(unsigned int dmanr, const char * device_id);