disable i2c interface to px4io board that we don;t have on a quanton
get sensors and sensor IO working:
  fix pinouts on I2C sensors, as baro and compas are on I2C bus 3, unlike px4.
  enable spi2 bus, which is disabled by default in px4.  needed on quanton, as that's where the mpu6000 is wired to.
  disable SDMMC loading on SPI3 bus, as we don't have a SDCARD, and there may be other stuff on SPI3 bus. ? ( probably not)
  point the red and blue LEDS at teh correct GPIO  ( PORTC PIN13 and PIN14 )
  disable code that supports the "extra" sensors on a px4 ( ie the l3gd20 and the bma280 ) , which we don't have on a quanton
simplify SPI init, as quanton don't have the additional gyro, accel, or SDCARD that typical PX4 has.