drm/msm/dsi_pll_10nm: Fix dividing the same numbers twice

In function dsi_pll_calc_dec_frac we are calculating the decimal
div start parameter by dividing the decimal multiple by the
fractional multiplier: the remainder of that operation is stored
to then get programmed to the fractional divider registers of
the PLL.

It's useless to call div_u64_rem to get the remainder and *then*
call div_u64 to get the division result, as the first is already
giving that result: let's fix it by just caring about the result
of div_u64_rem.
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

@@ -172,9 +172,7 @@ static void dsi_pll_calc_dec_frac(struct dsi_pll_10nm *pll)
 
 	multiplier = 1 << config->frac_bits;
 	dec_multiple = div_u64(pll_freq * multiplier, divider);
-	div_u64_rem(dec_multiple, multiplier, &frac);
-
-	dec = div_u64(dec_multiple, multiplier);
+	dec = div_u64_rem(dec_multiple, multiplier, &frac);
 
 	if (pll_freq <= 1900000000UL)
 		regs->pll_prop_gain_rate = 8;