sh: Clean up places that make 29-bit physical assumptions.

Signed-off-by: Stuart Menefy <stuart.menefy@st.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
diff --git a/include/asm-sh/scatterlist.h b/include/asm-sh/scatterlist.h
index a7d0d18..35ef9c3 100644
--- a/include/asm-sh/scatterlist.h
+++ b/include/asm-sh/scatterlist.h
@@ -1,6 +1,7 @@
 #ifndef __ASM_SH_SCATTERLIST_H
 #define __ASM_SH_SCATTERLIST_H
 
+#include <asm/pgtable.h>
 #include <asm/types.h>
 
 struct scatterlist {
@@ -13,7 +14,7 @@
     unsigned int length;
 };
 
-#define ISA_DMA_THRESHOLD (0x1fffffff)
+#define ISA_DMA_THRESHOLD	PHYS_ADDR_MASK
 
 /* These macros should be used after a pci_map_sg call has been done
  * to get bus addresses of each of the SG entries and their lengths.