sim/ppc: fixes for arguments to printf style functions

sim/ppc: fixes for arguments to printf style functions

After the recent series of fixes to mark more functions in the
simulator with ATTRIBUTE_PRINTF, there were some build failures in the
ppc sim due, in some cases, to bugs with the arguments being passed,
and in other cases, the issues were (maybe) less serious, with
arguments being the wrong size, or type, for the printf format being
used.

This commit fixes all of the issues that I ran into.

In each case I selected the easiest solution to the problem, which is
usually just casting the argument to the correct type.  If anyone
later on thinks the print format should change, please feel free to do
that.  What we have here should keep the simulator basically working
as it does currently, which is my goal with this commit.