iio: light: Add check for array bounds in veml6075_read_int_time_ms

The array contains only 5 elements, but the index calculated by
veml6075_read_int_time_index can range from 0 to 7,
which could lead to out-of-bounds access. The check prevents this issue.

Coverity Issue
CID 1574309: (#1 of 1): Out-of-bounds read (OVERRUN)
overrun-local: Overrunning array veml6075_it_ms of 5 4-byte
elements at element index 7 (byte offset 31) using
index int_index (which evaluates to 7)

This is hardening against potentially broken hardware. Good to have
but not necessary to backport.

Fixes: 3b82f43 ("iio: light: add VEML6075 UVA and UVB light sensor driver")
Signed-off-by: Karan Sanghavi <karansanghvi98@gmail.com>
Reviewed-by: Javier Carrasco <javier.carrasco.cruz@gmail.com>
Link: https://patch.msgid.link/Z7dnrEpKQdRZ2qFU@Emma
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/light/veml6075.c

@@ -195,13 +195,17 @@ static int veml6075_read_uv_direct(struct veml6075_data *data, int chan,
 
 static int veml6075_read_int_time_index(struct veml6075_data *data)
 {
-	int ret, conf;
+	int ret, conf, int_index;
 
 	ret = regmap_read(data->regmap, VEML6075_CMD_CONF, &conf);
 	if (ret < 0)
 		return ret;
 
-	return FIELD_GET(VEML6075_CONF_IT, conf);
+	int_index = FIELD_GET(VEML6075_CONF_IT, conf);
+	if (int_index >= ARRAY_SIZE(veml6075_it_ms))
+		return -EINVAL;
+
+	return int_index;
 }
 
 static int veml6075_read_int_time_ms(struct veml6075_data *data, int *val)