msm: camera: isp: Change dual IFE acquire sequence

In case of dual, acquire IFEs from a higher to lower idx.
The IFE with the higher hw_idx will be configured as slave.

CRs-Fixed: 2805265
Change-Id: I35e3af84e2ac6586056e6d74373642a85e5c797a
Signed-off-by: Karthik Anantha Ram <kartanan@codeaurora.org>