msm: camera: isp: validate in_port before accessing

in_port information we are getting from the UMD and accessing
it directly without validation which might lead to
corruption and device failure.

CRs-Fixed: 2629969
Change-Id: I0a1c57db9b94f9657427872ae6797635c6aed668
Signed-off-by: Tejas Prajapati <tpraja@codeaurora.org>