BMC support for PARISC machines

The last line of PARISC machines (C8000, RP34x0, etc.) have a BMC for
controlling temperature, fan speed and other stuff.  The BMC is
connected via a special bus and listed in the firmware device tree.
This change adds support for these BMCs to the IPMI driver.

Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Corey Minyard <cminyard@mvista.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>