Revert "drm/radeon/ci: disable mclk switching for high refresh rates (v2)"

This reverts commit 0157e2a8.

The reverted commit was backported and applied twice on the stable branch:
- First as commit 15de2e4c ("drm/radeon/ci: disable mclk switching for
high refresh rates (v2)")
- Then as commit 0157e2a8 ("drm/radeon/ci: disable mclk switching for
high refresh rates (v2)")

Fixes: 0157e2a8 ("drm/radeon/ci: disable mclk switching for high refresh rates (v2)")
Signed-off-by: Guillaume Bertholon <guillaume.bertholon@ens.fr>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>