drm/amd/display: Setup Second Stutter Watermark Implementation

[WHY & HOW]
Setup initial changes required to program another set of watermarks
for a 2nd stutter mode. The 2nd stutter mode will be lower power but
have higher enter/exit latencies.

PMFW to choose which stutter mode to use based on stutter efficiences
to see if original stutter (LP1) or low power stutter (LP2) will result
in better power savings.

Reviewed-by: Alvin Lee <alvin.lee2@amd.com>
Signed-off-by: Austin Zheng <Austin.Zheng@amd.com>
Signed-off-by: Alex Hung <alex.hung@amd.com>
Tested-by: Dan Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>