power: smb1360: Add multiple usages for the wakeup source

Previously, a single wakeup source is used across the driver for
multiple clients. If two or more clients held the wakeup source
and one client want to relax, it will be relaxed unintentionally
for other clients.

Manage the wakeup source status by using a global bitmap variable.
Each bit maps to one client, each client calling will update the
bitmap variable, and the wakeup source can only be relaxed if
all of the client has relaxed it intentionally.

CRs-Fixed: 846212
Change-Id: I8f93f19a8c639c8cde0b8798cc68e148d56b045e
Signed-off-by: Qiang Huang <qianghuang@codeaurora.org>