Input: uinput - breaks by goto out in uinput_ioctl_handler

The current implementation prevents us to add variable-length ioctl.
Use a bunch of gotos instead of break to allow us to do so.

No functional changes.

Signed-off-by: Benjamin Tisssoires <benjamin.tissoires@redhat.com>
Reviewed-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>