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/inc/hf/arch/plat/ffa.h b/inc/hf/arch/plat/ffa.h
index bfbc049..0d8813e 100644
--- a/inc/hf/arch/plat/ffa.h
+++ b/inc/hf/arch/plat/ffa.h
@@ -27,6 +27,11 @@
 				     struct ffa_value *ret);
 
 /**
+ * Checks whether managed exit is supported by given SP.
+ */
+bool plat_ffa_vm_managed_exit_supported(struct vm *vm);
+
+/**
  * Encodes memory handle according to section 5.10.2 of the FF-A v1.0 spec.
  */
 ffa_memory_handle_t plat_ffa_memory_handle_make(uint64_t index);