drm/amd/display: Cleanup uses of the analog flag

drm/amd/display: Cleanup uses of the analog flag

In the detect_link_and_local_sink() function, do not modify the
EDID capabilities of the display based on the connector. Instead,
respect the analog flag better and when the analog flag is set,
check that the connector indeed supports analog displays.

Suggested-by: Ray Wu <Ray.Wu@amd.com>
Signed-off-by: Timur Kristóf <timur.kristof@gmail.com>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Link: https://lore.kernel.org/r/20251113163348.137315-3-timur.kristof@gmail.com
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>