clk: socfpga: stratix10: Optimize local variables

Since readl() returns a u32, the local variable reg can also have the
data type u32. Furthermore, mdiv and refdiv are derived from reg and can
also be a u32.

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

  WARNING: do_div() does a 64-by-32 division, please consider using div64_ul instead

Compile-tested only.

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
Signed-off-by: Dinh Nguyen <dinguyen@kernel.org>

drivers/clk/socfpga/clk-pll-s10.c

@@ -83,9 +83,9 @@ static unsigned long clk_pll_recalc_rate(struct clk_hw *hwclk,
 					 unsigned long parent_rate)
 {
 	struct socfpga_pll *socfpgaclk = to_socfpga_clk(hwclk);
-	unsigned long mdiv;
-	unsigned long refdiv;
-	unsigned long reg;
+	u32 mdiv;
+	u32 refdiv;
+	u32 reg;
 	unsigned long long vco_freq;
 
 	/* read VCO1 reg for numerator and denominator */