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/renesas/common/plat_pm.c b/plat/renesas/common/plat_pm.c
index 9810596..871dddc 100644
--- a/plat/renesas/common/plat_pm.c
+++ b/plat/renesas/common/plat_pm.c
@@ -302,7 +302,7 @@
 	.system_off			= rcar_system_off,
 	.system_reset			= rcar_system_reset,
 	.validate_power_state		= rcar_validate_power_state,
-	.pwr_domain_pwr_down_wfi	= rcar_pwr_domain_pwr_down_wfi,
+	.pwr_domain_pwr_down		= rcar_pwr_domain_pwr_down_wfi,
 #if RCAR_SYSTEM_SUSPEND
 	.get_sys_suspend_power_state	= rcar_get_sys_suspend_power_state,
 #endif