drm/i915/mtl: Fix voltage_level for cdclk==480MHz

Allow MTL to use voltage level 1 for 480MHz cdclk,
instead of the voltage level 2 that it's currently using.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231128115138.13238-6-ville.syrjala@linux.intel.comReviewed-by: Gustavo Sousa <gustavo.sousa@intel.com>

drivers/gpu/drm/i915/display/intel_cdclk.c

@@ -3516,7 +3516,7 @@ static const struct intel_cdclk_funcs mtl_cdclk_funcs = {
 	.get_cdclk = bxt_get_cdclk,
 	.set_cdclk = bxt_set_cdclk,
 	.modeset_calc_cdclk = bxt_modeset_calc_cdclk,
-	.calc_voltage_level = tgl_calc_voltage_level,
+	.calc_voltage_level = rplu_calc_voltage_level,
 };
 
 static const struct intel_cdclk_funcs rplu_cdclk_funcs = {