FlyingF4: Add panic codes for sensor errors

 * 1 pulse - flash chip
 * 2 pulses - MPU6050
 * 3 pulses - HMC5883
 * 4 pulses - MS5611
 * 5 pulses - gyro I2C bus locked
 * 6 pulses - mag/baro I2C bus locked
FlyingF4 Panic Codes: Do not trigger watchdog

Watchdog timer is 250 ms
Merge pull request #421 from peabody124/flyingf4_panic_codes

FlyingF4: Add panic codes for sensor errors