drm/amd/display: Fix Silence warnings

drm/amd/display: Fix Silence warnings

Also affects: freesync, hdcp, info_packet, power

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

[How] In .c/.h 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>