msm: camera: Remove the cleanup function from vb2 ops

The vb2 cleanup function is needed to be supported
if there is any per buffer cleanup required from camera driver.
But there is no specific cleanup required per buffer
from camera side, instead cleanup is already done on complete queue.

Change-Id: Ie163e10a036652fd6a1ff21fcf420c026a8af19d
Signed-off-by: Lakshmi Narayana Kalavala <lkalaval@codeaurora.org>