Unify hdp related function into hdp structure for hdp version 6.
V2: Remove hdp invalidate function as hdp v6 doesn't have read cache.
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>