refactor(interrupts): remove api_interrupt_inject

api_interrupt_inject and vcpu_interrupt_inject were performing the
same function, as the next argument was never being used. So just
use vcpu_interrupt_inject.

Also remove unnecessary if statement from vcpu_interrupt_inject.

Signed-off-by: Daniel Boulby <daniel.boulby@arm.com>
Change-Id: I36c5157b7961e5a85b3e485f0a309b5dddf7c21a
diff --git a/src/arch/fake/hypervisor/ffa.c b/src/arch/fake/hypervisor/ffa.c
index b01e967..66cee73 100644
--- a/src/arch/fake/hypervisor/ffa.c
+++ b/src/arch/fake/hypervisor/ffa.c
@@ -354,11 +354,9 @@
 }
 
 bool ffa_interrupts_inject_notification_pending_interrupt(
-	struct vcpu_locked target_locked, struct vcpu_locked current_locked,
-	struct vm_locked receiver_locked)
+	struct vcpu_locked target_locked, struct vm_locked receiver_locked)
 {
 	(void)target_locked;
-	(void)current_locked;
 	(void)receiver_locked;
 
 	return false;