drm/amd/display: Fix up coverity issues

[Why]
Coverity found various high-impact issues that need resolving.

[How]
Fix  some buffer overruns and uninitialized variables.

Signed-off-by: Aric Cyr <aric.cyr@amd.com>
Reviewed-by: Tony Cheng <Tony.Cheng@amd.com>
Acked-by: Leo Li <sunpeng.li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
3 files changed