thermal/drivers/rcar_gen3: Fix comment typo

Fix typo to millidegree Celsius. This aligns the comment with
another comment later on the same function. No functional change.

Signed-off-by: Marek Vasut <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Daniel Lezcano <[e-mail]>

drivers/thermal/renesas/rcar_gen3_thermal.c

···
 	const struct equation_set_coef *coef;
 	int adj, decicelsius, reg, thcode;
 
-	/* Read register and convert to mili Celsius */
+	/* Read register and convert to millidegree Celsius */
 	reg = rcar_gen3_thermal_read(tsc, REG_GEN3_TEMP) & CTEMP_MASK;
 
 	if (reg < tsc->thcode[1]) {