drm/amd: Add name to modes from amdgpu_connector_add_common_modes()

[Why]
When DC adds common modes it adds modes with a string to match what
they are. Non-DC doesn't. This can be inconsistent when turning on/off
DC support.

[How]
Add a name member to common_modes[] and copy it into the drm display
mode.

Cc: Timur Kristóf <timur.kristof@gmail.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Timur Kristóf <timur.kristof@gmail.com>
Link: https://lore.kernel.org/r/20250924161624.1975819-6-mario.limonciello@amd.com


Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>