Add Light SDMA (LSDMA) block and related function. LSDMA
is a small instance of SDMA mainly for kernel driver use.
Signed-off-by: NLikun Gao <Likun.Gao@amd.com>
Reviewed-by: NHawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>