msm: camera: Increase the max supported cameras to 5

Increase the max supported physical id of camera to 4. With this change
we can now add new device node with cell-id equal to 4.

Change-Id: Ic70f73be78410ea4ff730a5096def3d106bbfc3a
Signed-off-by: Tony Lijo Jose <tjose@codeaurora.org>