drivers: iio: light: Fix sparse warnings

Fixing below warnings:

drivers/iio/light/max44000.c:217:18: warning: cast to restricted __be16
drivers/iio/light/max44000.c:217:18: warning: cast to restricted __be16
drivers/iio/light/max44000.c:217:18: warning: cast to restricted __be16
drivers/iio/light/max44000.c:217:18: warning: cast to restricted __be16

Signed-off-by: Sandhya Bankar <bankarsandhya512@gmail.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

drivers/iio/light/max44000.c

@@ -204,17 +204,18 @@ static int max44000_write_alspga(struct max44000_data *data, int val)
 static int max44000_read_alsval(struct max44000_data *data)
 {
 	u16 regval;
+	__be16 val;
 	int alstim, ret;
 
 	ret = regmap_bulk_read(data->regmap, MAX44000_REG_ALS_DATA_HI,
-			       &regval, sizeof(regval));
+			       &val, sizeof(val));
 	if (ret < 0)
 		return ret;
 	alstim = ret = max44000_read_alstim(data);
 	if (ret < 0)
 		return ret;
 
-	regval = be16_to_cpu(regval);
+	regval = be16_to_cpu(val);
 
 	/*
 	 * Overflow is explained on datasheet page 17.