drm/amdgpu: allow unaligned memory access (v2)

Set up the CP and SDMA for proper unaligned memory access.
Required for OpenCL 2.x

v2: udpate commit message

Signed-off-by: Jack Xiao <Jack.Xiao@amd.com>
Reviewed-by: Monk Liu <monk.liu@amd.com>
Reviewed-by: Jammy Zhou <Jammy.Zhou@amd.com>