nouveau: dup fd before passing it to device

nouveau: dup fd before passing it to device

nouveau screens are reused for the same device node. However in the
scenario where we create screen 1, screen 2, and then delete screen 1,
the surrounding code might also close the original device node. To
protect against this, dup the fd and use the dup'd fd in the
nouveau_device. Also tell the nouveau_device that it is the owner of the
fd so that it will be closed on destruction.

Also make sure to free the nouveau_device in case of any failure.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=79823
Signed-off-by: Ilia Mirkin <imirkin@alum.mit.edu>
Cc: "10.2" <mesa-stable@lists.freedesktop.org>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@ubuntu.com>