Add support for ICM-42688P gyro/accel (Skystars H743 Dual Gyro)

[Ferris3]

Description:
The Skystars H743 Dual Gyro flight controller ships with two ICM-42688P IMUs.
INAV 8.0.1 does not detect these sensors (GYRO/ACC show UNAVAILABLE).
Betaflight 4.5.2 correctly detects them as ICM42688P and both gyros work.

Steps tested:

• Flash INAV 8.0.1, target SKYSTARSH743HD
• status shows: GYRO=UNAVAILABLE, ACC=UNAVAILABLE
• get acc_hardware shows no ICM42688P option
• Barometer (BMP280) works
• Same hardware flashed with Betaflight → both gyros detected as ICM42688P

Request:
Please port or add driver support for ICM-42688P (from Betaflight's icm42xxx driver).