drm/amdgpu: Don't offset by 2 in FRU EEPROM

Read buffers no longer expose the I2C address, and so we don't need to
offset by two when we get the read data.

Cc: Alex Deucher <Alexander.Deucher@amd.com>
Cc: Kent Russell <kent.russell@amd.com>
Cc: Andrey Grodzovsky <Andrey.Grodzovsky@amd.com>
Fixes: bd607166 ("drm/amdgpu: Enable reading FRU chip via I2C v3")
Signed-off-by: Luben Tuikov <luben.tuikov@amd.com>
Acked-by: Harish Kasiviswanathan <Harish.Kasiviswanathan@amd.com>
Reviewed-by: Kent Russell <kent.russell@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>