feat(ff-a): add managed exit field in the manifest

Moving setting to enable/disable managed exit support from messaging
method field to a separate field in partition manifest. As of DEN0077A
FF-A v1.1 Beta0 section 5.2, managed exit support is moved out of
messaging-method field and is described in a separate field.

Signed-off-by: Maksims Svecovs <maksims.svecovs@arm.com>
Change-Id: I87506d7213b88d5a18073bea7357c381605d8b33
diff --git a/src/api.c b/src/api.c
index 8a90a27..82619e0 100644
--- a/src/api.c
+++ b/src/api.c
@@ -228,7 +228,7 @@
  */
 static bool api_ffa_is_managed_exit_ongoing(struct vcpu_locked vcpu_locked)
 {
-	return (vm_managed_exit_supported(vcpu_locked.vcpu->vm) &&
+	return (plat_ffa_vm_managed_exit_supported(vcpu_locked.vcpu->vm) &&
 		vcpu_locked.vcpu->processing_managed_exit);
 }