[coreboot] updated http://www.coreboot.org/Build_from_Windows page

[Scott Duplichan]

Hello,

I made some improvements to this wiki page:
http://www.coreboot.org/Build_from_Windows

1) The prebuilt windows build environment now uses
   util/crossgcc/buildgcc to build cross compilers. The
   previous release uses a manually built cross compiler.

2) Both 4.4.4 and 4.5.0 cross compiler versions are included.
   Version 4.5.0 is more tolerant of microsoft-isms found in
   some snapshots of the next generation AMD reference code.

3) Now, all coreboot projects can build from this environment.
   The previous release was missing libgcc.a, which is needed
   by some of the projects.

4) The example now includes the steps for building seabios.

Thanks,
Scott