[PATCH] x86-64: Fix 32bit sendfile

If we use 64bit kernel on ia64/x86_64/s390 architecture, and we run
32bit binary on 32bit compatibility mode, sendfile system call seems be
not set offset argument.

This is because sendfile's return value is not zero but the code regards
the result by return value is zero or not.

This problem will be affect to ia64/x86_64/s390 and not affect to other
architecture does not affect other architecture (mips/parisc/ppc64/sparc64).

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>