v4l2: Handle corrupted buffer with empty payload

v4l2: Handle corrupted buffer with empty payload

This allow skipping buffer flagged with ERROR that has no payload.
This is typical behaviour when a recovererable error occured during
capture in the driver, but that no valid data was ever written into that
buffer. This patch also translate V4L2_BUF_FLAG_ERROR into
GST_BUFFER_FLAG_CORRUPTED. Hence decoding error produce
by decoder due to missing frames will now be correctly marked. Finally,
this fixes a buffer leak when EOS is reached.

https://bugzilla.gnome.org/show_bug.cgi?id=740040