When an i2c WRITE gets an i2c defer or short i2c ack reply, we are
supposed to switch the request from I2C_WRITE to I2C_WRITE_STATUS_UPDATE
when we continue to poll for the completion of the request.

v2: Don't assume DP_AUX_I2C_WRITE is 0 even though it is, to make the
    code more obvious to the casual reader (Jani)
Acked-by: NAlex Deucher <alexander.deucher@amd.com>
Reviewed-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
[danvet: Resolve conflict due to changed context.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>