wcnss: Update pm wake api's for 4.19 kernel

Wakeup_source_init and wakeup_source_trash api's
has been drepricated in 4.19 kernel. So, update
depricated api's with new api's.

Change-Id: I284a776f07953b33ffa5b7e3f9d0d5a742db1b4f
Signed-off-by: Sandeep Singh <sandsing@codeaurora.org>