media: mtk-vcodec: venc: fix return value when start_streaming fails

media: mtk-vcodec: venc: fix return value when start_streaming fails

BugLink: https://bugs.launchpad.net/bugs/1951822
[ Upstream commit 065a7c66bd8b21db212fa86187ff12f0cac6ea6d ]

In case vb2ops_venc_start_streaming fails, the error value
is overwritten by the ret value of pm_runtime_put which might
be 0. Fix it.

Fixes: 985c73693fe5a (" media: mtk-vcodec: Separating mtk encoder driver")
Signed-off-by: Dafna Hirschfeld <dafna.hirschfeld@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Paolo Pisati <paolo.pisati@canonical.com>