add ESP32 large buffer support (doesnt fix bno085 but worth a short)

cc @caternuson

Author: ladyada

Adafruit_I2CDevice.cpp

@@ -13,6 +13,8 @@ Adafruit_I2CDevice::Adafruit_I2CDevice(uint8_t addr, TwoWire *theWire) {
   _begun = false;
 #ifdef ARDUINO_ARCH_SAMD
   _maxBufferSize = 250; // as defined in Wire.h's RingBuffer
+#elif defined(ESP32)
+  _maxBufferSize = I2C_BUFFER_LENGTH;
 #else
   _maxBufferSize = 32;
 #endif