iio: gyro: mpu3050: fix sign of raw angular velocity readings

The MPU-3050 gyroscope output registers hold 16-bit two's complement
values; the angular velocity channels are declared with .sign = 's'.
When mpu3050_read_raw() handles IIO_CHAN_INFO_RAW it reads the register
via a big-endian regmap_bulk_read() and assigns it with:

	*val = be16_to_cpu(raw_val);

be16_to_cpu() yields an unsigned 16-bit quantity, so negative rates
(bit 15 set) are reported to userspace as large positive integers
(e.g. -1 becomes 65535) instead of the correct negative value.

Cast to s16 before the assignment, matching the temperature channel a
few lines above which already handles the sign correctly.

Fixes: 3904b28efb ("iio: gyro: Add driver for the MPU-3050 gyroscope")
Cc: stable@vger.kernel.org
Assisted-by: Claude:claude-opus-4
Signed-off-by: Cong Nguyen <congnt264@gmail.com>
Reviewed-by: Linus Walleij <linusw@kernel.org>
Reviewed-by: Joshua Crofts <joshua.crofts1@gmail.com>
Reviewed-by: David Lechner <dlechner@baylibre.com>
Signed-off-by: Jonathan Cameron <jonathan.cameron@oss.qualcomm.com>

drivers/iio/gyro/mpu3050-core.c

@@ -356,7 +356,7 @@ static int mpu3050_read_raw(struct iio_dev *indio_dev,
 				goto out_read_raw_unlock;
 			}
 
-			*val = be16_to_cpu(raw_val);
+			*val = (s16)be16_to_cpu(raw_val);
 			ret = IIO_VAL_INT;
 
 			goto out_read_raw_unlock;