PSCI: Build option to enable D-Caches early in warmboot

This patch introduces a build option to enable D-cache early on the CPU
after warm boot. This is applicable for platforms which do not require
interconnect programming to enable cache coherency (eg: single cluster
platforms). If this option is enabled, then warm boot path enables
D-caches immediately after enabling MMU.

Fixes ARM-Software/tf-issues#456

Change-Id: I44c8787d116d7217837ced3bcf0b1d3441c8d80e
Signed-off-by: Soby Mathew <soby.mathew@arm.com>
diff --git a/lib/psci/psci_on.c b/lib/psci/psci_on.c
index 675ed66..76e67a3 100644
--- a/lib/psci/psci_on.c
+++ b/lib/psci/psci_on.c
@@ -165,7 +165,7 @@
 	 */
 	psci_plat_pm_ops->pwr_domain_on_finish(state_info);
 
-#if !HW_ASSISTED_COHERENCY
+#if !(HW_ASSISTED_COHERENCY || WARMBOOT_ENABLE_DCACHE_EARLY)
 	/*
 	 * Arch. management: Enable data cache and manage stack memory
 	 */