git: kernel - add short-form mutex calls

[Matthew Dillon]

    This low-hanging fruit is driving me nuts, it isn't as low hanging
    as I thought it would be.  I'm going to hold off on the networking
    byte order branch and work on another area.

    I am going to simplify the lwkt_token API a bit by hiding the tokrefs
    completely, so they don't have to be declared on the kernel stack anymore,
    and I am going to integrate a MP lock switch feature into the lwkt_ token
    to create something that is easier to use and will make the MPSAFE
    porting work easier.

    Theoretically this will allow us to lock up subsystems with lwkt tokens
    so we don't have to worry about lock ordering issues, and then use
    sysctls to turn off the MP lock integrated into the tokens.

    I think one of the reasons lwkt_tokens aren't used as much as they could
    be is due to the complexity of having to declare the tokref on the
    kernel stack.  With these changes it may be possible to finally lock up
    the I/O paths.

						-Matt