drm/amd/display: fix code to control 48mhz refclk

[Why]
The SMU message to enable this feature looks at argument. Previous code
didn't send right argument. This change will allow the feature to be
be enabled.

[How]
Fixed one issue where SMU message to enable the feature was sent without
setting the parameter.

Signed-off-by: Eric Yang <Eric.Yang2@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>