media: TDA1997x: fix tda1997x_query_dv_timings() return value

Correctly propagate the tda1997x_detect_std error value.

Signed-off-by: Krzysztof Hałasa <khalasa@piap.pl>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>