gpio: fix line flag validation in lineevent_create

commit 5ca2f54b597c816df54ff1b28eb99cf7262b955d upstream.

lineevent_create should not allow any of GPIOHANDLE_REQUEST_OUTPUT,
GPIOHANDLE_REQUEST_OPEN_DRAIN or GPIOHANDLE_REQUEST_OPEN_SOURCE to be set.

Fixes: d7c51b47 ("gpio: userspace ABI for reading/writing GPIO lines")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Kent Gibson <warthog618@gmail.com>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>