aboot: Add warmboot indication to command line.

Determine for a given target, if booting in warm boot.
This information can be used by subsequent HLOS to perform
required action.

CRs-fixed: 612619
Change-Id: Ib734e2ce556151f44646784abb4a69f30e0db684
diff --git a/target/init.c b/target/init.c
index bd5b325..c5a202c 100644
--- a/target/init.c
+++ b/target/init.c
@@ -176,3 +176,9 @@
 __WEAK void target_usb_phy_reset(void)
 {
 }
+
+/* determine if target is in warm boot. */
+__WEAK bool target_warm_boot(void)
+{
+	return false;
+}