Some vmalloc failure paths do not report OOM conditions.

Add warn_alloc_failed, which also does a dump_stack, to those failure
paths.

This allows more site specific vmalloc failure logging message printks to
be removed.
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>