mm-camera: Implement scratch buffer support

Implement scratch buffer support in ISP buffer manager
and add some additional logic to handle streams that
require scratch buffer.

Change-Id: I05e71da988729e8b831a391e99eccd196a62fd03
Signed-off-by: Konstantin Motov <kmotov@codeaurora.org>
Signed-off-by: Nagesh Subba Reddy <nageshsreddy@codeaurora.org>
Signed-off-by: Mansoor Aftab <maftab@codeaurora.org>