msm: camera: Remove duplicate video device list initialization.

When a video device is registered through video_register_device,
the fh_lock and fh_list variables are already initialized. So we
dont need to explicitly initialize them during v4l2 event queue
setup. Doing this overwrites the fh_list in some cases like
mctl pp node, where each instance can have its own eventHandle but
linked to the mctl pp video node. This can cause video device list
corruption in some usecases like HDR. Remove this extra
initialization for v4l2 nodes which register their video devices.
For native nodes using v4l2 event handles, add the initialization
before setting up the v4l2 event queue.
Move the function setup_v4l2_event_queue and
destroy_v4l2_event_queue into msm_cam_server.c for better code
organization.

Change-Id: Ifcd148d5d0187cf33a6ea49977010e88d6043698
Signed-off-by: Kiran Kumar H N <hurlisal@codeaurora.org>