msm: adsprpc: fix compilation errors in fastrpc driver

Update APIs used in fastrpc driver according to the new function
implementation of wakeup_source_register.

Change-Id: I278fb2e2954908001776240f6321c7de4deb3357
Acked-by: Maitreyi Gupta <maitreyi@qti.qualcomm.com>
Signed-off-by: Jeya R <jeyr@codeaurora.org>