msm: bam_dmux: delay premature uplink wakeup votes

Delay processing of wakeup votes until after bam has been initialized.
Premature votes can cause bam_dmux to go into the fatal error state if
wakeup votes are processed before the modem has powered up for the first
time.

Change-Id: I18e6963d6b1003a08c117233c9465795c7aab5b2
Signed-off-by: Jeffrey Hugo <jhugo@codeaurora.org>