drm/i915/skl: Updated the gen6_init_rps_frequencies function

On SKL the frequency is specified in units of 16.66 MHZ, barring the
RP_STATE_CAP(0x5998) register, which still reports frequency in units
of 50 MHZ. So an extra conversion is required in gen6_init_rps_frequencies
function for SKL, to store the frequency values as per the actual hardware unit.

v2: Corrected the conversion from 50 to 16.66 MHZ (Ville)
Signed-off-by: NAkash Goel <akash.goel@intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_pm.c

@@ -4181,6 +4181,13 @@ static void gen6_init_rps_frequencies(struct drm_device *dev)
 	dev_priv->rps.rp0_freq		= (rp_state_cap >>  0) & 0xff;
 	dev_priv->rps.rp1_freq		= (rp_state_cap >>  8) & 0xff;
 	dev_priv->rps.min_freq		= (rp_state_cap >> 16) & 0xff;
+	if (IS_SKYLAKE(dev)) {
+		/* Store the frequency values in 16.66 MHZ units, which is
+		   the natural hardware unit for SKL */
+		dev_priv->rps.rp0_freq *= GEN9_FREQ_SCALER;
+		dev_priv->rps.rp1_freq *= GEN9_FREQ_SCALER;
+		dev_priv->rps.min_freq *= GEN9_FREQ_SCALER;
+	}
 	/* hw_max = RP0 until we check for overclocking */
 	dev_priv->rps.max_freq		= dev_priv->rps.rp0_freq;