msm: camera: ispif: Validate vfe_intf parameter

Validate vfe_intf parameter to avoid invalid register access.

Conflicts:
	drivers/media/platform/msm/camera_v2/ispif/msm_ispif.c

Bug: 19141503
Change-Id: Ie0b57071cc5fca1c48d3a5e2e7819f9af9ff544c
Signed-off-by: Suman Mukherjee <sumam@codeaurora.org>
Signed-off-by: Patrick Tjin <pattjin@google.com>