drm/nouveau/i2c: resume use of i2c-algo-bit, rather than custom stack

Previous issues with i2c-algo-bit have now been resolved.

This is a revert of f553b79c03f0dbd52f6f03abe8233a2bef8cbd0d mostly,
due to fixes in the i2c core repairing the original issue, this code
isn't required and was causing regressions.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Reported-by: Nick Bowler <nbowler@elliptictech.com>
Tested-by: Nick Bowler <nbowler@elliptictech.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>