AP_HAL: initialize I2C manager

Add I2CManager to AP_HAL's contructor.

libraries/AP_HAL/HAL.h

@@ -21,6 +21,7 @@ public:
         AP_HAL::UARTDriver* _uartC, // telem1
         AP_HAL::UARTDriver* _uartD, // telem2
         AP_HAL::UARTDriver* _uartE, // 2nd GPS
+        AP_HAL::I2CDeviceManager* _i2c_mgr,
         AP_HAL::I2CDriver*  _i2c0,
         AP_HAL::I2CDriver*  _i2c1,
         AP_HAL::I2CDriver*  _i2c2,
@@ -40,6 +41,7 @@ public:
         uartC(_uartC),
         uartD(_uartD),
         uartE(_uartE),
+        i2c_mgr(_i2c_mgr),
         i2c(_i2c0),
         i2c1(_i2c1),
         i2c2(_i2c2),
@@ -80,6 +82,7 @@ public:
     AP_HAL::UARTDriver* uartC;
     AP_HAL::UARTDriver* uartD;
     AP_HAL::UARTDriver* uartE;
+    AP_HAL::I2CDeviceManager* i2c_mgr;
     AP_HAL::I2CDriver*  i2c;
     AP_HAL::I2CDriver*  i2c1;
     AP_HAL::I2CDriver*  i2c2;