Staging: iio: Remove explicit comparison to NULL

This patch simplifies pointer comparison to NULL and makes code
easier to read. Warning found by checkpatch.pl.

Signed-off-by: Cristina Opriceana <[e-mail]>
Reviewed-by: Daniel Baluta <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/staging/iio/frequency/ad9832.c

···
 	}
 
 	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
-	if (indio_dev == NULL) {
+	if (!indio_dev) {
 		ret = -ENOMEM;
 		goto error_disable_reg;
 	}

drivers/staging/iio/frequency/ad9834.c

···
 	}
 
 	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
-	if (indio_dev == NULL) {
+	if (!indio_dev) {
 		ret = -ENOMEM;
 		goto error_disable_reg;
 	}