ARM: use phys_addr_t for DMA zone sizes

In order to specify a DMA zone size of 4GB on LPAE systems, the sizes need
to be 64-bit. So make machine_desc.dma_zone_size and arm_dma_zone_size be
phys_addr_t instead of unsigned long.

Signed-off-by: Rob Herring <rob.herring@calxeda.com>
diff --git a/arch/arm/include/asm/mach/arch.h b/arch/arm/include/asm/mach/arch.h
index 441efc4..d91b168 100644
--- a/arch/arm/include/asm/mach/arch.h
+++ b/arch/arm/include/asm/mach/arch.h
@@ -35,7 +35,7 @@
 	unsigned int		nr_irqs;	/* number of IRQs */
 
 #ifdef CONFIG_ZONE_DMA
-	unsigned long		dma_zone_size;	/* size of DMA-able area */
+	phys_addr_t		dma_zone_size;	/* size of DMA-able area */
 #endif
 
 	unsigned int		video_start;	/* start of video RAM	*/