refactor: rename implicit_completion_signal

Rename "implicit_completion_signal" to
"requires_deactivate_call".

Signed-off-by: J-Alves <joao.alves@arm.com>
Change-Id: I298bf74a9cf8dd64f68109eb8c4b8848407eb536
diff --git a/inc/hf/vcpu.h b/inc/hf/vcpu.h
index 92bb929..a7c74f3 100644
--- a/inc/hf/vcpu.h
+++ b/inc/hf/vcpu.h
@@ -194,7 +194,7 @@
 	 * while running). This variable helps SPMC to keep a track of such
 	 * mechanism and perform appropriate bookkeeping.
 	 */
-	bool implicit_completion_signal;
+	bool requires_deactivate_call;
 
 	/** SP call chain. */
 	struct call_chain call_chain;