e1000: fix buliding complaint

hw/net/e1000e_core.c:56: warning: e1000e_set_interrupt_cause declared inline after being called
hw/net/e1000e_core.c:56: warning: previous declaration of e1000e_set_interrupt_cause was here

Signed-off-by: Gonglei <arei.gonglei@huawei.com>
Reviewed-by: Dmitry Fleytman <dmitry@daynix.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>

hw/net/e1000e_core.c

@@ -2168,7 +2168,7 @@ e1000e_update_interrupt_state(E1000ECore *core)
     }
 }
 
-static inline void
+static void
 e1000e_set_interrupt_cause(E1000ECore *core, uint32_t val)
 {
     trace_e1000e_irq_set_cause_entry(val, core->mac[ICR]);