ARM: 7908/1: mm: Fix the arm_dma_limit calculation

Current code is using PHYS_OFFSET to calculate the arm_dma_limit which
will lead to wrong calculations in cases where PHYS_OFFSET is updated
runtime.

So fix the code by using __pv_phys_offset instead of PHYS_OFFSET.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Nicolas Pitre <nicolas.pitre@linaro.org>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/mm/init.c

@@ -229,7 +229,7 @@ void __init setup_dma_zone(const struct machine_desc *mdesc)
 #ifdef CONFIG_ZONE_DMA
 	if (mdesc->dma_zone_size) {
 		arm_dma_zone_size = mdesc->dma_zone_size;
-		arm_dma_limit = PHYS_OFFSET + arm_dma_zone_size - 1;
+		arm_dma_limit = __pv_phys_offset + arm_dma_zone_size - 1;
 	} else
 		arm_dma_limit = 0xffffffff;
 	arm_dma_pfn_limit = arm_dma_limit >> PAGE_SHIFT;