i.MX31: Make SPI more tolerant by resetting and forcing a reconfigure of the interface if an error ever happens. Better handle PMIC GPIO interrupt; it definitely doesn't low-pulse PRIINT (remains high if sources become active again or stay active while acking) so needed rising edge may never happen in such a case-- use high-level detection rather than rising edge. Optimize the reg/clr/set/mod functions a bit since they get more regular use now.
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@19903 a1c6a512-1295-4272-9138-f99709370657