i2c: imx-lpi2c: fix type char overflow issue when calculating the clock cycle

Claim clkhi and clklo as integer type to avoid possible calculation
errors caused by data overflow.

Fixes: a55fa9d0e42e ("i2c: imx-lpi2c: add low power i2c bus driver")
Signed-off-by: Clark Wang <[e-mail]>
Signed-off-by: Carlos Song <[e-mail]>
Reviewed-by: Andi Shyti <[e-mail]>
Signed-off-by: Wolfram Sang <[e-mail]>

drivers/i2c/busses/i2c-imx-lpi2c.c

···
 /* CLKLO = I2C_CLK_RATIO * CLKHI, SETHOLD = CLKHI, DATAVD = CLKHI/2 */
 static int lpi2c_imx_config(struct lpi2c_imx_struct *lpi2c_imx)
 {
-	u8 prescale, filt, sethold, clkhi, clklo, datavd;
-	unsigned int clk_rate, clk_cycle;
+	u8 prescale, filt, sethold, datavd;
+	unsigned int clk_rate, clk_cycle, clkhi, clklo;
 	enum lpi2c_imx_pincfg pincfg;
 	unsigned int temp;