[I2C] I2CSlaveConfig now has default parameters

src/shared/drivers/i2c/I2CDriver.h

@@ -106,9 +106,11 @@ public:
             slaveAddress;  ///< Slave address without shifts (in BIT7 addressing
                            ///< |9-bit unused|7-bit address|; in BIT10
                            ///< addressing |6-bit unused|10-bit address|).
-        I2CDriver::Addressing addressing;  ///< Addressing mode of the device.
-        I2CDriver::Speed speed;            ///< Speed mode of the communication.
-        bool MSBFirst;  ///< Registers with lower values are the MSB of
+        I2CDriver::Addressing addressing =
+            I2CDriver::Addressing::BIT7;  ///< Addressing mode of the device.
+        I2CDriver::Speed speed =
+            I2CDriver::Speed::MAX_SPEED;  ///< Speed mode of the communication.
+        bool MSBFirst = false;  ///< Registers with lower values are the MSB of
                                 ///< multi-byte registers
     } I2CSlaveConfig;