Input: uinput - fix returning EPOLLOUT from uinput_poll

Always return EPOLLOUT from uinput_poll to allow polling /dev/uinput
for writable state.

Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Link: https://lore.kernel.org/r/20191204025014.5189-1-marcel@holtmann.org


Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>