Add 32 bit version of plat_get_syscnt_freq

Added plat_get_syscnt_freq2, which is a 32 bit variant of the 64 bit
plat_get_syscnt_freq. The old one has been flagged as deprecated.
Common code has been updated to use this new version. Porting guide
has been updated.

Change-Id: I9e913544926c418970972bfe7d81ee88b4da837e
diff --git a/services/std_svc/psci/psci_suspend.c b/services/std_svc/psci/psci_suspend.c
index bd0c5db..367bb32 100644
--- a/services/std_svc/psci/psci_suspend.c
+++ b/services/std_svc/psci/psci_suspend.c
@@ -214,7 +214,7 @@
 void psci_cpu_suspend_finish(unsigned int cpu_idx,
 			     psci_power_state_t *state_info)
 {
-	unsigned long long counter_freq;
+	unsigned int counter_freq;
 	unsigned int max_off_lvl;
 
 	/* Ensure we have been woken up from a suspended state */
@@ -238,7 +238,7 @@
 	psci_do_pwrup_cache_maintenance();
 
 	/* Re-init the cntfrq_el0 register */
-	counter_freq = plat_get_syscnt_freq();
+	counter_freq = plat_get_syscnt_freq2();
 	write_cntfrq_el0(counter_freq);
 
 	/*