intel_edison_fab_c.c: Fix edison disabled pwm stuck at high
intel_edison_fab_c.c: Fix edison disabled pwm stuck at high

Edison pwm can stuck at high if pin is disabled during ON pwm peroid.
Workaround is to force zero duty time before disabling the pin.

Signed-off-by: Billy Bai <ada898d31d4bbde5c98a26776df5ec39f3cb4772@outlook.com>
Signed-off-by: Brendan Le Foll <3e0e8c4069934e8b47d99704927a85c66c0ceb33@intel.com>

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