PSCI: Do stat accounting for retention/standby states

Perform stat accounting for retention/standby states also when
requested at multiple power levels.

Change-Id: I2c495ea7cdff8619bde323fb641cd84408eb5762
Signed-off-by: dp-arm <dimitris.papastamos@arm.com>

lib/psci/psci_suspend.c

@@ -251,6 +251,10 @@ exit:
 	    PMF_NO_CACHE_MAINT);
 #endif
 
+#if ENABLE_PSCI_STAT
+	plat_psci_stat_accounting_start(state_info);
+#endif
+
 	/*
 	 * We will reach here if only retention/standby states have been
 	 * requested at multiple power levels. This means that the cpu
@@ -258,6 +262,11 @@ exit:
 	 */
 	wfi();
 
+#if ENABLE_PSCI_STAT
+	plat_psci_stat_accounting_stop(state_info);
+	psci_stats_update_pwr_up(end_pwrlvl, state_info);
+#endif
+
 #if ENABLE_RUNTIME_INSTRUMENTATION
 	PMF_CAPTURE_TIMESTAMP(rt_instr_svc,
 	    RT_INSTR_EXIT_HW_LOW_PWR,