If kzalloc() failed and then evdev_open_device() fails, evdev_open()
will pass a vmalloc'ed pointer to kfree.

This might fix https://bugzilla.kernel.org/show_bug.cgi?id=88401, where
there was a crash in kfree().
Reported-by: Christian Casteyde <casteyde.christian@free.fr>
Belatedly-Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Henrik Rydberg <rydberg@euromail.se>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>