drm/amd/display: Fix Compiler warnings in dmub

drm/amd/display: Fix Compiler warnings in dmub

[Why]
Resolve compiler warnings by marking unused parameters explicitly.

[How]
In .c and .h files, keep parameter names in signatures and add a
line with`(void)param;`  inside the function body

Preserved function signatures and avoids breaking code paths that
may reference the parameter under conditional compilation.

Reviewed-by: Aric Cyr <aric.cyr@amd.com>
Signed-off-by: Gaghik Khachatrian <gaghik.khachatrian@amd.com>
Signed-off-by: Chuanyu Tseng <chuanyu.tseng@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>