[PATCH] hwpmc(4) syscall arguments fix

[Oleksandr Tymoshenko]

     I ran into problems trying to get hwpmc to work on 64-bit MIPS
system with big endian byte order. Turned out hwpmc syscall handler
is byte-order and register_t size agnostic unlike the rest of syscalls.
The best solution I have so far is a copy sys/sysproto.h approach:
http://people.freebsd.org/~gonzo/patches/hwpmc-syscall.diff

Any other ideas how to get it fixed in more clean way?