Previously this RTC was using the file system-based i2c interface in
/dev. Since the RTC is initialized pretty early on during system init,
we call open() before stdin/stdout/stderr have been opened. RTEMS
assumes that stdin == 0, stdout == 1, etc., and fails when that isn't
the case. In particular, when stdin != 0, RTEMS assumes that it wasn't
configured with a console driver and skips opening stdout/stderr,
leading to confusing issues with the standard I/O streams.
Closes#5284
074cb8f337