drm/amd/display: fix typo "to found" -> "to find"

[Why]
Typo in amdgpu_dm error message:
"Failed to found connector for link!"
[How]
1. Replace with:
"Failed to find connector for link!"
2. Fix indentation checkpatch warnings.

Signed-off-by: Roman Li <roman.li@amd.com>
Reviewed-by: Zhan Liu <Zhan.Liu@amd.com>
Acked-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>