msm: camera: memmgr: Add refcount to track umd in use buffers

Currently krefcount is using by umd and kmd. Due to sometimes
there is issue in umd, such as release twice. That maybe causes
buffer release before kmd access the buffer. This commit add
a new refcount to track umd in use buffers and use current krefcount
to track kmd in use buffers. For the same buffer use in kmd and umd
only when all refcount become zero, the buffer start to release.

CRs-Fixed: 3692103
Change-Id: I5a58d9bab4c82bdb192d6a6a3d2b3d254dc04c9e
Signed-off-by: zhuo <quic_zhuo@quicinc.com>