I2C: sparse cleanups again, based on comments from lkml

This is more like the original code.
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

drivers/i2c/chips/it87.c

@@ -170,11 +170,8 @@ static inline u8 FAN_TO_REG(long rpm, int div)
 static int DIV_TO_REG(int val)
 {
 	int answer = 0;
-	val >>= 1;
-	while (val) {
+	while ((val >>= 1) != 0)
 		answer++;
-		val >>= 1;
-	}
 	return answer;
 }
 #define DIV_FROM_REG(val) (1 << (val))