drm/amd/pm/smu13: Remove unused smu_v13_0_init_display_count

smu_v13_0_init_display_count() was added in 2020 by
commit c05d1c40 ("drm/amd/swsmu: add aldebaran smu13 ip support (v3)")
but is unused.

See discussion on:
https://lore.kernel.org/all/DM4PR12MB5165D85BD85BC8FC8BF7A3B48E88A@DM4PR12MB5165.namprd12.prod.outlook.com/


that it really isn't neede.

Remove it.

Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>