spi: sprd: Pass offset instead of physical address to adi_read/_write()

spi: sprd: Pass offset instead of physical address to adi_read/_write()

The register offset would be added a physical address base and then pass to
the function sprd_adt_read()/_write() each time before calling them. So we
can do that within these two functions instead, that would make the code
more clear.

Signed-off-by: Chunyan Zhang <chunyan.zhang@unisoc.com>
Link: https://lore.kernel.org/r/20210824070212.2089255-1-zhang.lyra@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>