Removed default values from internal functions

- Also removed useless else from loraphy_target.h

features/lorawan/lorastack/mac/LoRaMac.h

@@ -370,14 +370,14 @@ public:
      *
      * @return LORAWAN_STATUS_OK or a negative error code on failure.
      */
-    lorawan_status_t prepare_join(const lorawan_connect_t *params, bool is_otaa = true);
+    lorawan_status_t prepare_join(const lorawan_connect_t *params, bool is_otaa);
 
     /**
      * @brief join Joins the network.
      * @param is_otaa True if joining is to be done using OTAA, false for ABP.
      * @return LORAWAN_STATUS_OK or a negative error code on failure.
      */
-    lorawan_status_t join(bool is_otaa = true);
+    lorawan_status_t join(bool is_otaa);
 
 private:
     /**

features/lorawan/lorastack/phy/loraphy_target.h

@@ -60,8 +60,6 @@
  #elif MBED_CONF_LORA_PHY    == US915_HYBRID
   #include "lorawan/lorastack/phy/LoRaPHYUS915Hybrid.h"
   #define LoRaPHY_region LoRaPHYUS915Hybrid
- #else
-  #error "Unsupported region, check your configuration."
  #endif //MBED_CONF_LORA_PHY == VALUE
 #else
  #error "Must set LoRa PHY layer parameters."