destructors for I2C and SPI should be virtual.

src/drivers/device/i2c.h

@@ -88,7 +88,7 @@ protected:
 	    uint16_t address,
 	    uint32_t frequency,
 	    int irq = 0);
-	~I2C();
+	virtual ~I2C();
 
 	virtual int	init();
 

src/drivers/device/spi.h

@@ -71,7 +71,7 @@ protected:
 	    enum spi_mode_e mode,
 	    uint32_t frequency,
 	    int irq = 0);
-	~SPI();
+	virtual ~SPI();
 
 	virtual int	init();