The call to wakeup_source_register() in ipa_probe() does not do what
it was intended to do.  Call device_init_wakeup() in ipa_setup()
instead, to set the IPA device as wakeup-capable and to initially
enable wakeup capability.

When we receive a SUSPEND interrupt, call pm_wakeup_dev_event()
with a zero processing time, to simply call for a resume without
any other processing.  The ipa_resume() call will take care of
waking things up again, and will handle receiving the packet.

Note that this gets rid of a clock reference counting bug that
occurred when handling an IPA SUSPEND interrupt.  Specifically,
ipa_suspend_handler() took an IPA clock reference *in addition*
to the one taken by ipa_resume().  There is no need to back-port
this fix however, because it only affects code that was not
previously working (this patch is part of fixing that).
Signed-off-by: Alex Elder <elder@linaro.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>