iommu/dma: Fix IOVA reserve dma ranges

iommu/dma: Fix IOVA reserve dma ranges

Fix IOVA reserve failure in the case when address of first memory region
listed in dma-ranges is equal to 0x0.

Fixes: aadad097cd46f ("iommu/dma: Reserve IOVA for PCIe inaccessible DMA address")
Signed-off-by: Srinath Mannam <srinath.mannam@broadcom.com>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Tested-by: Sven Peter <sven@svenpeter.dev>
Link: https://lore.kernel.org/r/20200914072319.6091-1-srinath.mannam@broadcom.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>