media: em28xx: make v4l2-compliance happier by starting sequence on zero

commit afeaade90db4c5dab93f326d9582be1d5954a198 upstream.

The v4l2-compliance tool complains if a video doesn't start
with a zero sequence number.

While this shouldn't cause any real problem for apps, let's
make it happier, in order to better check the v4l2-compliance
differences before and after patchsets.

This is actually an old issue. It is there since at least its
videobuf2 conversion, e. g. changeset 3829fadc461 ("[media]
em28xx: convert to videobuf2"), if VB1 wouldn't suffer from
the same issue.

Cc: stable@vger.kernel.org
Fixes: d3829fadc461 ("[media] em28xx: convert to videobuf2")
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/media/usb/em28xx/em28xx-video.c b/drivers/media/usb/em28xx/em28xx-video.c
index 5b94418..1ed7ba3 100644
--- a/drivers/media/usb/em28xx/em28xx-video.c
+++ b/drivers/media/usb/em28xx/em28xx-video.c
@@ -1290,6 +1290,8 @@
 {
 	struct em28xx *dev = priv;
 
+	dev->v4l2->field_count = 0;
+
 	/*
 	 * In the case of non-AC97 volume controls, we still need
 	 * to do some setups at em28xx, in order to mute/unmute