drm/amd/display: Call dpmm when checking mode support

[WHY]
In check_mode_supported, we should validate that the required clocks
can be successfully mapped to DPM levels.

This ensures we only apply dynamic ODM optimizations to modes that
are supported without dynamic ODM optimizations to begin with.

[HOW]
Call dpmm to check that the display config can successfully be
mapped to a DPM level.

Reviewed-by: Chaitanya Dhere <chaitanya.dhere@amd.com>
Cc: Mario Limonciello <mario.limonciello@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
Signed-off-by: Alex Hung <alex.hung@amd.com>
Signed-off-by: George Shen <george.shen@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>