ARM: OMAP 2: Camera: Don't return -EIO in VIDIOC_DQBUF

vidioc_dqbuf returned -EIO in a number of cases which is probably a bit
confusing for many programs. This patch changes behaviour so that the
next intact frame is always returned (i.e. never -EIO anymore).

-EAGAIN is returned in non-blocking mode.

Signed-off-by: Sakari Ailus <sakari.ailus@nokia.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>