V4L/DVB: Add a new ERROR flag for DQBUF after recoverable streaming errors

This flag is intended to indicate streaming errors, which might have
resulted in corrupted video data in the buffer, but the buffer can still
be reused and streaming may continue.

Setting this flag and returning 0 is different from returning EIO. The
latter should now indicate more serious (unrecoverable) errors.

This patch also solves a problem with the ioctl handling code in
vl42-ioctl.c, which does not copy buffer identification data back to the
userspace when EIO is returned, so there is no way for applications
to discover on which buffer the operation failed in such cases.

Signed-off-by: Pawel Osciak <p.osciak@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>