chore(docs): drop the "wfi" from `pwr_domain_pwr_down_wfi`

To allow for generic handling of a wakeup, this hook is no longer
expected to call wfi itself. Update the name everywhere to reflect this
expectation so that future platform implementers don't get misled.

Change-Id: Ic33f0b6da74592ad6778fd802c2f0b85223af614
Signed-off-by: Boyan Karatotev <boyan.karatotev@arm.com>
diff --git a/plat/qemu/common/qemu_pm.c b/plat/qemu/common/qemu_pm.c
index 5f64d70..7893c81 100644
--- a/plat/qemu/common/qemu_pm.c
+++ b/plat/qemu/common/qemu_pm.c
@@ -218,7 +218,7 @@
 	.cpu_standby = qemu_cpu_standby,
 	.pwr_domain_on = qemu_pwr_domain_on,
 	.pwr_domain_off = qemu_pwr_domain_off,
-	.pwr_domain_pwr_down_wfi = qemu_pwr_domain_pwr_down_wfi,
+	.pwr_domain_pwr_down = qemu_pwr_domain_pwr_down_wfi,
 	.pwr_domain_suspend = qemu_pwr_domain_suspend,
 	.pwr_domain_on_finish = qemu_pwr_domain_on_finish,
 	.pwr_domain_suspend_finish = qemu_pwr_domain_suspend_finish,