[PATCH] inotify: check for NULL inode in inotify_d_instantiate

The spufs file system creates files in a directory before instantiating the
directory itself, which causes a NULL pointer access in
inotify_d_instantiate since c32ccd87.

I'd like to keep this behavior since it means that the user will not have
access to files in the directory before I know that I succeed in creating
everything in it.  This patch adds a simple check for the inode to keep
that working.

Signed-off-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>
Acked-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>