drm/msm/dsi_pll_7nm: 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 7nm:
remove the TODO by simply using that variable. This is a copy of
196145eb ("drm/msm/dsi_pll_10nm: Solve TODO for multiplier frac_bits
assignment").
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Abhinav Kumar <abhinavk@codeaurora.org>
Signed-off-by: Rob Clark <robdclark@chromium.org>

drivers/gpu/drm/msm/dsi/pll/dsi_pll_7nm.c

@@ -509,6 +509,7 @@ static unsigned long dsi_pll_7nm_vco_recalc_rate(struct clk_hw *hw,
 {
 	struct msm_dsi_pll *pll = hw_clk_to_pll(hw);
 	struct dsi_pll_7nm *pll_7nm = to_pll_7nm(pll);
+	struct dsi_pll_config *config = &pll_7nm->pll_configuration;
 	void __iomem *base = pll_7nm->mmio;
 	u64 ref_clk = pll_7nm->vco_ref_clk_rate;
 	u64 vco_rate = 0x0;
@@ -529,9 +530,8 @@ static unsigned long dsi_pll_7nm_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);