Technically, this should not matter. The only time this would make any
difference would be if the FLASH functions modified data that was already
within the data cache. If the lines were left valid and then the cache
disabled, when the cache was re-enabled, the lines in the cache could
override the changes in memory, leading to an inconsistent state. So,
for safety's sake, we should leave the invalidate calls in there. BTW,
as far as I can see the only time this could cause a problem would be
on the "inquire" function - the one that computes the size and shape of
the FLASH. If that data were already in the cache, then things could
go awry. The only other routines only write to the FLASH and should not
be touching memory anyway.