model in use for a given platform (__PROG26 vs __PROG32), then pulls
in <arm/types.h>. Change each ARM port to pull in <arm/arm26/types.h>
or <arm/arm32/types.h> as appropriate. Change all references to PROG26
and PROG32 to __PROG26 and __PROG32. Eliminate the opt_progmode.h
header file.