neuron: block_client: Fix init loop

Depending on timing there is a chance the channel initialization will
happen at different intervals. When this happens, the first channel
wakeup will be cleared by the init loop and never be set again by the
channel init.  This leads to a stall in init because both channels
will never have both their wakeups set to signal channel init done.

Change-Id: I435e78c3e4b83cf6b827d3827f35d1e6a1b297fa
Acked-by: Chris Henroid <chenroid@qti.qualcomm.com>
Signed-off-by: Chris Lew <clew@codeaurora.org>