i2c: move over to using std::expected for reads

Moves over to using std::expected for reads. This was mostly
an experiment, but I ended up testing and liking it more
than our out-value implementation. Put it up and make the world
a slightly better place.

Tested: put onto nvl32-obmc, i2c ready still works

Change-Id: I637cee5175fc684b6d02096a525b61ab6f4ab918
Signed-off-by: Marc Olberding <molberding@nvidia.com>
3 files changed