These fixes address regressions caused by http://gerrit-git.amd.com/c/compute/ec/hip/+/337601
Currently we're converting a 1D offset into a 3D offset, which doesn't make much sense once you consider the fact that this offset is relative to a different origin than our current 3D offset.
I traced through our blit kernels in VDI - the copy buffer rect path is able to handle immediate offsets in the 3D buffer via the amd::BufferRect::start_ parameter.
Instead of adjusting the offset, simply adjust the start of the region.
Change-Id: Ic8797a2c8ac0ad106f246f61ff06ca1ca03d3058
[ROCm/hip commit: 1bd640b659]
Vladislav Sytchenko
5bfbf130ba