Holding a wakelock avoids suspend power collapse, which
allow the BT idle timer to kick in, which eventually
initiates BT low power modes.
CRs-Fixed: 361067
Change-Id: I93e3950b6f854e70dbce092a5529120ec008c2b8
Signed-off-by: Rahul Kashyap <rkashyap@codeaurora.org>