of: unittest: 64 bit dma address test requires arch support

If an architecture does not support 64 bit dma addresses then testing
for an expected dma address >= 0x100000000 will fail.

Fixes: e0d07278

 ("dma-mapping: introduce DMA range map, supplanting dma_pfn_offset")
Signed-off-by: Frank Rowand <frank.rowand@sony.com>
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20211212221852.233295-1-frowand.list@gmail.com