msm: smd_tty: replace wake lock with wakeup source

Wake locks have been deprecated.

Remove deprecated wake lock calls and replace with wakeup sources and
power-management calls.

Change-Id: Ibb3d84ae20ed0af43254e46b344be8d86e97c717
Signed-off-by: Eric Holmberg <eholmber@codeaurora.org>