Noted by David Woodhouse <dwmw2@infradead.org>

Here's a fix for the ppc64 crash during boot.  This corrects the
offending function to use more conventional error codes.  I'll follow up
with return code cleanups for the entire module, and for RTAS code,
since these are probably too big for 2.6.11. 
Signed-off-by: John Rose <johnrose@austin.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>