testing/sensortest: Update device path
Device paths are now named `/dev/sensor/sensor_...`:
****************************************************************************/
#define ARRAYSIZE(a) (sizeof(a) / sizeof(a)[0])
-#define DEVNAME_FMT "/dev/sensor/%s"
+#define DEVNAME_FMT "/dev/sensor/sensor_%s"
#define DEVNAME_MAX 64
/****************************************************************************
