msm: camera: isp: Add support for dual isp

Add support for dual ISP. Change allows for address sync,
external regupdate and image address configuraion for dual
case. Also adds csid test gen for dual isp.

Change-Id: Id3cb4b45c3562f7257007bc2b91436d07e26a368
Signed-off-by: Ravikishore Pampana <rpampana@codeaurora.org>
Signed-off-by: Karthik Anantha Ram <kartanan@codeaurora.org>