[PATCH] powerpc/opal: add warning for unimplemented OPAL message type

I found that there are unimplemented OPAL message types "OPAL_MSG_EPOW" and 
"OPAL_MSG_DPO" in PowerNV Platform. If skiboot send such messages to kernel, 
nothing will happen(notifier_call_chain() will silently drop it). So I add a warning 
to inform what has happened, is it necessary? 

Signed-off-by: Wen Pu <redacted>
---

diff --git a/arch/powerpc/platforms/powernv/opal.c b/arch/powerpc/platforms/powernv/opal.c
index f084afa..ef498ab 100644
--- a/arch/powerpc/platforms/powernv/opal.c
+++ b/arch/powerpc/platforms/powernv/opal.c

@@ -281,6 +281,10 @@ static void opal_handle_message(void)
  pr_warning("%s: Unknown message type: %u\n", __func__, type);
  return;
  }
+ if(type == OPAL_MSG_EPOW || type == OPAL_MSG_DPO) {
+ pr_warning("%s: Unimplemented message type: %u\n", __func__, type);
+ return;
+ }
  opal_message_do_notify(type, (void *)&msg);
 }
---

Thanks!
Wen Pu