i386, amd64 will be moved into an arch/ subdirectory

[Matthew Dillon <dillon@xxxxxxxxxxxxxxxxxxxx>]

    I am going to reorganize the architecture topology in /usr/src/sys/
    over the next week.

    /usr/src/sys/i386	-> /usr/src/sys/arch/i386
    /usr/src/sys/amd64	-> /usr/src/sys/arch/amd64
    /usr/src/sys/conf/*.i386 -> /usr/src/sys/arch/*.i386
    /usr/src/sys/conf/*.amd64 -> /usr/src/sys/arch/*.amd64

    The kernel config files will be moved *out* of the architecture
    specific directories and consolidated into a single generic
    subdirectory called /usr/src/sys/config.

    /usr/src/sys/<arch>/conf/BLAH -> /usr/src/sys/config/BLAH

    TARGET and TARGET_ARCH will be removed.  The machine architecture will
    be extracted from the 'machine' directive in the kernel config file.

    I have already done the repo-copy to create /usr/src/sys/arch.  I
    am not going to move the rest of the files or hook any of it up until
    probably Tuesday or Wednesday, though, because I will likely be gone
    for two days and I don't want to break the build before I leave.

						-Matt