POSIX: Fixes for HRT implementation of simulated HW clock polling
POSIX: Fixes for HRT implementation of simulated HW clock polling

There is a race condition for the accel and mag polling rates.
Whichever one gets set first, the other will be uninitialized.

Set the mag polling rate to 1ms if uninitilized.

Signed-off-by: Mark Charlebois <f1891e7fc976ae1bd489627e2954fb730751d728@gmail.com>

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