xen/arm: change parameter name 'vcpu' in domain() function definition.

In the current version of domain() function, the declaration
(correctly) uses the parameter name 'v' while the definition uses the
parameter name 'vcpu'.
Since it is common to use 'v' to denote a vCPU, change the parameter
name 'vcpu' of function definition to 'v', thus fixing a violation of
MISRA C:2012 Rule 8.3.

Signed-off-by: Federico Serafini <federico.serafini@bugseng.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>

xen/arch/arm/domain.c

@@ -1155,15 +1155,15 @@ void vcpu_block_unless_event_pending(struct vcpu *v)
         vcpu_unblock(current);
 }
 
-void vcpu_kick(struct vcpu *vcpu)
+void vcpu_kick(struct vcpu *v)
 {
-    bool running = vcpu->is_running;
+    bool running = v->is_running;
 
-    vcpu_unblock(vcpu);
-    if ( running && vcpu != current )
+    vcpu_unblock(v);
+    if ( running && v != current )
     {
         perfc_incr(vcpu_kick);
-        smp_send_event_check_mask(cpumask_of(vcpu->processor));
+        smp_send_event_check_mask(cpumask_of(v->processor));
     }
 }