this will be mostly not useful to anyone since flash is attached to
qspi, and using flash chips that don't use the *entire* qspi interface
will severly slow down the chip. the code overhead is minimal right now,
but if we also fix interrupt support on qspi pins this will
change (adding more code to potentially hot paths, using more memory for
wakers that are never used, and preventing the qspi gpio irq from being
used in software interrupts as RTIC applications may want to do).
dca1777a2f