[PATCH] powerpc: Initialise hvlpevent_queue.lock correctly

When I changed the hvlpevent_queue code to use a spinlock instead of a
custom atomic (719d1cd8) I didn't
initialise the lock anywhere, oops.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>