add PIN23 into mapping (it was missing, thus would have caused the offsets to be off by 1 starting with PIN24); add PIN7 & PIN8 (not quite sure why the other IO's have been omitted, but I needed PIN7 and PIN8). Found bank/mux settings in i.MX233 documentation.  Note the PIN designation corresponds to the signal name, and the silkscreen under the GPIO connector (NOT the actual pin # on the connector, nor the processor pin, nor the Linux GPIO name!)