Fix various minor IDE warnings.

src/main/common/printf.c

@@ -139,6 +139,7 @@ void tfp_format(void *putp, putcf putf, char *fmt, va_list va)
                 break;
             case '%':
                 putf(putp, ch);
+                break;
             default:
                 break;
             }

src/main/drivers/bus_spi.c

@@ -180,7 +180,7 @@ uint8_t spiTransferByte(SPI_TypeDef *instance, uint8_t data)
 #ifdef STM32F10X
     return ((uint8_t)SPI_I2S_ReceiveData(instance));
 #endif
-    }
+}
 
 bool spiTransfer(SPI_TypeDef *instance, uint8_t *out, uint8_t *in, int len)
 {

src/main/main.c

@@ -66,8 +66,6 @@
 
 #include "build_config.h"
 
-extern rcReadRawDataPtr rcReadRawFunc;
-
 extern uint32_t previousTime;
 
 #ifdef SOFTSERIAL_LOOPBACK

src/main/sensors/initialisation.c

@@ -155,8 +155,6 @@
 #undef USE_ACC_MMA8452
 #endif
 
-extern uint16_t batteryWarningVoltage;
-extern uint8_t batteryCellCount;
 extern float magneticDeclination;
 
 extern gyro_t gyro;