Currently, enabling wakeup for the IPA device doesn't occur until
the setup phase of initialization (in ipa_power_setup()).

There is no need to delay doing that, however.  We can conveniently
do it during the config phase, in ipa_interrupt_config(), where we
enable power management wakeup mode for the IPA interrupt.

Moving the device_init_wakeup() out of ipa_power_setup() leaves that
function empty, so it can just be eliminated.

Similarly, rearrange all of the matching inverse calls, disabling
device wakeup in ipa_interrupt_deconfig() and removing that function
as well.
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>