mmc: mtk-sd: Improve data type in msdc_timeout_cal()

The local variable clk_ns uses at most 32 bits and can be a u32.

Replace the 64-by-32 do_div() division with a standard divison.

Since do_div() casts the divisor to u32 anyway, changing the data type
of clk_ns to u32 also removes the following Coccinelle/coccicheck
warning reported by do_div.cocci:

  WARNING: do_div() does a 64-by-32 division, please consider using div64_u64 instead

Use min_t(u32,,) to simplify the code and improve its readability.
Signed-off-by: Thorsten Blum <thorsten.blum@toblux.com>
Link: https://lore.kernel.org/r/20240818142300.64156-2-thorsten.blum@toblux.comSigned-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/host/mtk-sd.c

@@ -795,14 +795,13 @@ static void msdc_unprepare_data(struct msdc_host *host, struct mmc_data *data)
 static u64 msdc_timeout_cal(struct msdc_host *host, u64 ns, u64 clks)
 {
 	struct mmc_host *mmc = mmc_from_priv(host);
-	u64 timeout, clk_ns;
-	u32 mode = 0;
+	u64 timeout;
+	u32 clk_ns, mode = 0;
 
 	if (mmc->actual_clock == 0) {
 		timeout = 0;
 	} else {
-		clk_ns  = 1000000000ULL;
-		do_div(clk_ns, mmc->actual_clock);
+		clk_ns = 1000000000U / mmc->actual_clock;
 		timeout = ns + clk_ns - 1;
 		do_div(timeout, clk_ns);
 		timeout += clks;
@@ -831,7 +830,7 @@ static void msdc_set_timeout(struct msdc_host *host, u64 ns, u64 clks)
 
 	timeout = msdc_timeout_cal(host, ns, clks);
 	sdr_set_field(host->base + SDC_CFG, SDC_CFG_DTOC,
-		      (u32)(timeout > 255 ? 255 : timeout));
+		      min_t(u32, timeout, 255));
 }
 
 static void msdc_set_busy_timeout(struct msdc_host *host, u64 ns, u64 clks)
@@ -840,7 +839,7 @@ static void msdc_set_busy_timeout(struct msdc_host *host, u64 ns, u64 clks)
 
 	timeout = msdc_timeout_cal(host, ns, clks);
 	sdr_set_field(host->base + SDC_CFG, SDC_CFG_WRDTOC,
-		      (u32)(timeout > 8191 ? 8191 : timeout));
+		      min_t(u32, timeout, 8191));
 }
 
 static void msdc_gate_clock(struct msdc_host *host)