Fix: Target power soft-start for older native hardware

[dragonmux]

Detailed description

Due to a small accident with Git, the initial commit for this patch is already on main as b83657e, so in this PR we fix a small mistake with the platform initialisation that saw the timer used by soft-start failing to be powered up on hardware older than the BMP v2.3 hardware.

This enables tpwr soft-start for hw1 and up.

Your checklist for this pull request

• I've read the Code of Conduct
• I've read the guidelines for contributing to this repository
• It builds for hardware native (make PROBE_HOST=native)
• It builds as BMDA (make PROBE_HOST=hosted)
• I've tested it to the best of my ability
• My commit messages provide a useful short description of what the commits do

Closing issues

[esden]

I have tested this patch on HW1,2 and 4. I am very satisfied with the results. For reference here some screenshots of the different hardware versios. Yellow trace is the PWR_BR (power enable pin, it is reverse logic, high is off low is on) the blue trace is the 3.3V rail.

HW1 without pwm

HW1 with pwm

HW2 without pwm

HW2 with pwm

HW4 without pwm

HW4 with pwm

As this is a significant improvement, let's merge this, and backport to v1.8 and v1.9 firmwares and create some new point releases. ;)