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 f7adb0577ff9c0dfc4e833b2ec2c25511d9b9c3b.

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