[PATCH] Alpha: strncpy() fix

As it turned out after recent SCSI changes, strncpy() was broken -
it mixed up the return values from __stxncpy() in registers $24 and $27.

Thanks to Mathieu Chouquet-Stringer for tracking down the problem
and providing an excellent test case.

Signed-off-by: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>