setAuxI2CEnabled should also get enabled for units with Compass working in I2C mode

[dmarszk]

Currently only when operating the MPU through SPI, I2C AUX mode is enabled automatically during initialization. When operating through I2C, the application has to do it to enable readouts from the compass.

esp32-MPU-driver/src/MPU.cpp

Line 1785 in 82a6092

if (MPU_ERR_CHECK(setAuxI2CEnabled(true))) return err;