[ARM] Move ISA_DMA_THRESHOLD to asm/memory.h

This allows machine classes to override ISA_DMA_THRESHOLD as
necessary.

include/asm-arm/memory.h

@@ -57,6 +57,16 @@
 #error Top of user space clashes with start of module space
 #endif
 
+/*
+ * The DMA mask corresponding to the maximum bus address allocatable
+ * using GFP_DMA.  The default here places no restriction on DMA
+ * allocations.  This must be the smallest DMA mask in the system,
+ * so a successful GFP_DMA allocation will always satisfy this.
+ */
+#ifndef ISA_DMA_THRESHOLD
+#define ISA_DMA_THRESHOLD	(0xffffffffULL)
+#endif
+
 #ifndef __ASSEMBLY__
 
 /*

include/asm-arm/processor.h

@@ -25,7 +25,6 @@
 #include <asm/atomic.h>
 #include <asm/ptrace.h>
 #include <asm/procinfo.h>
-#include <asm/arch/memory.h>
 #include <asm/types.h>
 
 #define KERNEL_STACK_SIZE	PAGE_SIZE

include/asm-arm/scatterlist.h

 #ifndef _ASMARM_SCATTERLIST_H
 #define _ASMARM_SCATTERLIST_H
 
+#include <asm/memory.h>
 #include <asm/types.h>
 
 struct scatterlist {
@@ -21,6 +22,4 @@ struct scatterlist {
 #define sg_dma_address(sg)      ((sg)->dma_address)
 #define sg_dma_len(sg)          ((sg)->length)
 
-#define ISA_DMA_THRESHOLD (0xffffffff)
-
 #endif /* _ASMARM_SCATTERLIST_H */