Preliminary Coldfire Support

[Matt Thomas <matt%3am-software.com@localhost>]

I needed a distraction and I have this TWR-MCF5441X with a 250MHz 
MCF54418 with 128MB, 10/100 Ethernet, USB2, and SDHC which I've to 
get NetBSD running on.

So I decided to attack this backwards.  I started with the userland 
code and provided a minimal of kernel headers to get that to build.

I've added a new MACHINE_ARCH of coldfire and a MACHINE of evbcf.  
To avoid overloading m68k--netbsdelf I added a GNU_MACHINE_ARCH of 
m68k--netbsdelf-coldfire.  I'm not really happy with that.  Using 
m68kcf--netbsdelf resulted in other problems.  Maybe mcfisa--netbsd or 
coldfire--netbsd would be better but that requires more evaluation.

I've also used this to switch to Motorola syntax for most userland
assembly files.  Use -(reg) instead of (reg)@-, etc.

My changes are http://www.netbsd.org/~matt/coldfire-diffs.txt and
includes changes to 114 files and 152 new files.

Coldfire is a RISCy M68K.  A lot of instructions have been dumped
along with some addressing modes.  The biggest change is that 32-bit
displacements are not supported (think 32-bit pc relative) so that
requires a 2 instruction sequence on Coldfire.