drm/amd/display: Expand dmub_cmd operations

Update dmub_cmd to manipulate SDP control in replay FSM, add command
for panel_cntl, expand link rate enum, and increase the reserve byte.

Acked-by: Rodrigo Siqueira <rodrigo.siqueira@amd.com>
Signed-off-by: Anthony Koo <anthony.koo@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>