Pull coredump updates from Al Viro:
"Just a couple of patches this cycle: use of seek + write instead of
expanding truncate and minor header cleanup"
* 'work.coredump' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
coredump.h: move CONFIG_COREDUMP-only stuff inside the ifdef
coredump: don't bother with do_truncate()