[ARM] Ensure that both MAX_DMA_ADDRESS and ISA_DMA_THRESHOLD are defined

Both of these symbols should be defined by a platform, or neither
should be defined.  Ensure that all platforms conform.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/mach-pxa/include/mach/memory.h b/arch/arm/mach-pxa/include/mach/memory.h
index eac491c..f626730 100644
--- a/arch/arm/mach-pxa/include/mach/memory.h
+++ b/arch/arm/mach-pxa/include/mach/memory.h
@@ -37,6 +37,7 @@
 	cmx2xx_pci_adjust_zones(node, size, holes)
 
 #define ISA_DMA_THRESHOLD	(PHYS_OFFSET + SZ_64M - 1)
+#define MAX_DMA_ADDRESS		(PAGE_OFFSET + SZ_64M)
 #endif
 
 #endif