fix semaphore initialisation in max17048 driver

Previously, we were using the semaphore before initialising it; this is now fixed.

app/drivers/sensor/max17048/max17048.c

@@ -186,13 +186,15 @@ static int max17048_init(const struct device *dev) {
         return err;
     }
 
+    // the functions below need the semaphore, so initialise it here
+    k_sem_init(&drv_data->lock, 1, 1);
+
     // bring the device out of sleep
     set_sleep_enabled(dev, false);
 
     // set the default rcomp value -- 0x97, as stated in the datasheet
     set_rcomp_value(dev, 0x97);
 
-    k_sem_init(&drv_data->lock, 1, 1);
     LOG_INF("device initialised at 0x%x (version %d)", config->i2c_bus.addr, ic_version);
 
     return 0;