fix(ff-a): change assignment to equality in CHECK

Signed-off-by: Daniel Boulby <daniel.boulby@arm.com>
Change-Id: I760cd763259ce9644209c751d209de77cbd9a947
diff --git a/src/arch/aarch64/hypervisor/handler.c b/src/arch/aarch64/hypervisor/handler.c
index 2907d50..9d9250d 100644
--- a/src/arch/aarch64/hypervisor/handler.c
+++ b/src/arch/aarch64/hypervisor/handler.c
@@ -538,7 +538,7 @@
 
 		/* Refer FF-A v1.1 Beta0 section 7.4 bullet 2. */
 		if (current->processing_secure_interrupt) {
-			CHECK(current->state = VCPU_STATE_WAITING);
+			CHECK(current->state == VCPU_STATE_WAITING);
 
 			/* Secure interrupt pre-empted normal world. */
 			if (current->preempted_vcpu->vm->id ==