Revert "drm/amd/display: Don't return ddc result and read_bytes in same return value"

Revert "drm/amd/display: Don't return ddc result and read_bytes in same return value"

This reverts commit 6a3e425e7f3224074f259b2cb7ebaccac8e43ae9.

This breaks DDC in certain cases.  Revert for 4.18 and previous kernels.
For 4.19, this is fixed with the following more extensive patches:
drm/amd/display: Serialize is_dp_sink_present
drm/amd/display: Break out function to simply read aux reply
drm/amd/display: Return aux replies directly to DRM
drm/amd/display: Right shift AUX reply value sooner than later
drm/amd/display: Read AUX channel even if only status byte is returned

Link: https://lists.freedesktop.org/archives/amd-gfx/2018-July/023788.html
Acked-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org