dma-mapping: fix 32-bit overflow with CONFIG_ARM_LPAE=n

On r8a7791/koelsch and shmobile_defconfig, PCIe probing fails with:

    rcar-pcie fe000000.pcie: Adjusted size 0x0 invalid
    rcar-pcie: probe of fe000000.pcie failed with error -22

of_dma_get_range() returns the following map:

    cpu_start 0x40000000 dma_start 0x40000000 size 0x080000000 offset 0
    cpu_start 0x00000000 dma_start 0x00000000 size 0x100000000 offset 0

If CONFIG_ARM_LPAE=n, dma_addr_t is 32-bit.  Hence when assigning
r->dma_start + r->size to dma_end, this value will be truncated to
32-bit, yielding zero when processing the second table entry.
Consequently, both dma_start and dma_end will be zero, leading to a zero
size.

Fix this by changing the dma_start and dma_end variables from dma_addr_t
to u64.

Fixes: e0d07278

 ("dma-mapping: introduce DMA range map, supplanting dma_pfn_offset")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Christoph Hellwig <hch@lst.de>