85xx: separate PIXIS virtual from physical address

Added a PIXIS_BASE_PHYS for use as the physical address and maintain
PIXIS_BASE as the virtual address of the PIXIS fpga registers.

This allows us to deal with 36-bit phys on these boards in the future.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Acked-by: Andy Fleming <afleming@freescale.com>
diff --git a/board/freescale/mpc8536ds/tlb.c b/board/freescale/mpc8536ds/tlb.c
index c81a959..89d5097 100644
--- a/board/freescale/mpc8536ds/tlb.c
+++ b/board/freescale/mpc8536ds/tlb.c
@@ -41,7 +41,7 @@
 		      MAS3_SX|MAS3_SW|MAS3_SR, 0,
 		      0, 0, BOOKE_PAGESZ_4K, 0),
 
-	SET_TLB_ENTRY(0, PIXIS_BASE, PIXIS_BASE,
+	SET_TLB_ENTRY(0, PIXIS_BASE, PIXIS_BASE_PHYS,
 		      MAS3_SX|MAS3_SW|MAS3_SR, MAS2_I|MAS2_G,
 		      0, 0, BOOKE_PAGESZ_4K, 0),