drivers: sensor: Fix DHT20 build failure with CRC configured

Fixes the build error: 'crc' undeclared for
DHT20 sensor with CONFIG_DHT20_CRC option enabled.

Signed-off-by: Konrad Sikora <kontakt@konradsikora.pl>

drivers/sensor/aosong/dht20/dht20.c

@@ -190,7 +190,7 @@ static int dht20_read_sample(const struct device *dev, uint32_t *t_sample, uint3
 
 #if defined(CONFIG_DHT20_CRC)
 	/* Compute and check CRC with last byte of measurement data */
-	crc = crc8(rx_buf, 6, DHT20_CRC_POLYNOM, 0xFF, false);
+	uint8_t crc = crc8(rx_buf, 6, DHT20_CRC_POLYNOM, 0xFF, false);
 
 	if (crc != rx_buf[6]) {
 		rc = -EIO;

tests/drivers/build_all/sensor/prj.conf

@@ -16,3 +16,4 @@ CONFIG_W1=y
 CONFIG_SENSOR=y
 CONFIG_ICM42605_TRIGGER_NONE=y
 CONFIG_EMUL=y
+CONFIG_DHT20_CRC=y