msm: camera: memmgr: ref count for init and deinit

Shared memory is initialized by CRM and used by
ICP; with CRM not active the ICP would fail to
access the shared memory if memory manager is
deinit. Tracking open and close calls will help
ICP driver to access the shared memory if CRM
is not active.

CRs-Fixed: 3019488
Change-Id: Ifdf198c2e3593050573c66aeba69d50d131435b9
Signed-off-by: Tejas Prajapati <tpraja@codeaurora.org>