drm/msm/dsi_pll_10nm: Solve TODO for multiplier frac_bits assignment

The number of fractional registers bits is known and already set in
the frac_bits variable of the dsi_pll_config struct here in 10nm:
remove the TODO by simply using that variable.
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@somainline.org>
Signed-off-by: Rob Clark <robdclark@chromium.org>

drivers/gpu/drm/msm/dsi/pll/dsi_pll_10nm.c

@@ -481,6 +481,7 @@ static unsigned long dsi_pll_10nm_vco_recalc_rate(struct clk_hw *hw,
 {
 	struct msm_dsi_pll *pll = hw_clk_to_pll(hw);
 	struct dsi_pll_10nm *pll_10nm = to_pll_10nm(pll);
+	struct dsi_pll_config *config = &pll_10nm->pll_configuration;
 	void __iomem *base = pll_10nm->mmio;
 	u64 ref_clk = pll_10nm->vco_ref_clk_rate;
 	u64 vco_rate = 0x0;
@@ -501,9 +502,8 @@ static unsigned long dsi_pll_10nm_vco_recalc_rate(struct clk_hw *hw,
 	/*
 	 * TODO:
 	 *	1. Assumes prescaler is disabled
-	 *	2. Multiplier is 2^18. it should be 2^(num_of_frac_bits)
 	 */
-	multiplier = 1 << 18;
+	multiplier = 1 << config->frac_bits;
 	pll_freq = dec * (ref_clk * 2);
 	tmp64 = (ref_clk * 2 * frac);
 	pll_freq += div_u64(tmp64, multiplier);