drm/bridge: analogix_dp: properly handle zero sized AUX transactions

commit e82290a2e0e8ec5e836ecad1ca025021b3855c2d upstream.

Address only transactions without any data are valid and should not
be flagged as short transactions. Simply return the message size when
no transaction errors occured.

CC: stable@vger.kernel.org
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Reviewed-by: Robert Foss <rfoss@kernel.org>
Signed-off-by: Robert Foss <rfoss@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240318203925.2837689-1-l.stach@pengutronix.de


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>