Add missing implementations of derived_begin

Author: sebromero

src/PF1550/PF1550_IO_C33.h

@@ -45,6 +45,15 @@ class PF1550_IO_C33 : public PF1550_IO
     setBit(Register::CHARGER_LED_PWM, REG_LED_PWM_LED_EN_bp);
     /* Allow LED control by software. */
     setBit(Register::CHARGER_LED_CNFG, REG_LED_CNFG_LEDOVRD_bp);
+
+    if(getBit(Register::CHARGER_LED_PWM, REG_LED_PWM_LED_EN_bp) == 0){
+      return -1;
+    }
+
+    if(getBit(Register::CHARGER_LED_CNFG, REG_LED_CNFG_LEDOVRD_bp) == 0){
+      return -1;
+    }
+    return 0;
   }
 
 };

src/PF1550/PF1550_IO_Nicla_Vision.h

@@ -37,7 +37,7 @@ class PF1550_IO_Nicla_Vision : public PF1550_IO
 
 
 protected:
-  virtual int derived_begin() override { }
+  virtual int derived_begin() override { return 0; }
 };
 
 #endif /* PF1550_IO_NICLA_VISION_H_ */

src/PF1550/PF1550_IO_Portenta_H7.h

@@ -37,7 +37,7 @@ class PF1550_IO_Portenta_H7 : public PF1550_IO
 
 
 protected:
-  virtual int derived_begin() override { }
+  virtual int derived_begin() override { return 0;}
 };
 
 #endif /* PF1550_IO_ENVIEH747_H_ */