sim: bfin: fix thinko in SIC pin encoding

sim: bfin: fix thinko in SIC pin encoding

When encoding the SIC/pin info into unique input port ids, I used bases
of 100 when I meant to use 0x100.  Rather than simply fix the decoding
math in the different functions, create a few helper macros to simplify
the SIC/pin encoding and decoding steps.  This makes the resulting tables
nice & clear.

And now that pins are clear, the 533 and 537 port_event handlers may
easily be merged into one.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>