setting up a DEFAULTGPIO pulldown in bootloaders is a bad idea as it
overrides any hardware pullups that have been put in place as part of
a "hold in bootloader" mechanism. See discussion in #27360 for ELRS
note that this only impacts one board that I can see, the
BlitzF745AIO, due to the MCU vs DEFAULTGPIO interaction
this doesn't actually allow you to specify a default, despite the name
and a couple of hwdefs trying to use it that way.
This would have stopped being useful when we did the
compass-prority-table stuff - or before.
fixes#19765, an alternative to #19768
the advantage of this approach is it is less error prone, as the
actual position and size of the storage sectors is calculated