i965 clear/draw: set renderbuffer attachment as needing depth resolve

i965 clear/draw: set renderbuffer attachment as needing depth resolve

Previously we would mark a renderbuffer as needing a depth resolve.
But, to support layered rendering, we need to look at the attachment
instead, since the attachment knows if layered rendering is being
used.

Signed-off-by: Jordan Justen <jordan.l.justen@intel.com>
Reviewed-by: Paul Berry <stereotype441@gmail.com>
Reviewed-by: Chad Versace <chad.versace@linux.intel.com>