Right now the only way to force a cold reset is:
* The HAL itself detects it's needed, or
* The sysctl, setting all resets to be cold.
Trouble is, cold resets take quite a bit longer than warm resets.
However, there are situations where a cold reset would be nice.
Specifically, after a stuck beacon, BB/MAC hang, stuck calibration results,
etc.
The vendor HAL has a separate method to set the reset reason (which is
how HAL_RESET_BBPANIC gets set) which informs the HAL during the reset path
why it occured. This is almost but not quite the same; I may eventually
unify both approaches in the future.
This commit just extends HAL_RESET_TYPE to include both status (eg BBPANIC)
and type (eg do COLD.) None of the HAL code uses it yet though; that'll
come later.
It also is a big no-op in each HAL - I need to go teach each of the HALs
about cold/warm reset through this path.