Testing dw-i2c on as370 hardware

Follow these steps to test the driver:

1. Enable the test flag (I2C_AS370_DW_TEST) in the source file before compiling.
2. Build and flash as370

    fx set bringup.as370
    fx build
    fx vendor google flash-as370 zedboot

3. Success: Once booted, look for DW I2C test for AS370 passed in the kernel logs.
4. Failure: The test should ideally be completed immediately upon bootup. In case of any error or timeout, DW I2C test for AS370 failed will be printed within couple of seconds.