def.h: update add MPU6050 AUX users to MPU6050_I2C_AUX_MASTER

A few of them where still using the MPU6050_EN_I2C_BYPASS define which doesn't exist anymore.

This makes my Flyduino 9DOF board work properply.

Signed-off-by: Koen Kooi <koen@dominion.thruhere.net>