soc/arm/st_stm32: stm32wb: Remove stack reset from shutdown
soc/arm/st_stm32: stm32wb: Remove stack reset from shutdown

BLE stack reset should now be done in hci close function.
Remove from shutdown procedure.

Signed-off-by: Erwan Gouriou <de4d967452b83bb0e37525652734e7d9163b6a4c@linaro.org>

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