intel_scu_ipc: return -EIO for error condition in busy_loop

Signed-off-by: Hong Liu <hong.liu@intel.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Matthew Garrett <mjg@redhat.com>
diff --git a/drivers/platform/x86/intel_scu_ipc.c b/drivers/platform/x86/intel_scu_ipc.c
index 84a2d4b..23b6d46 100644
--- a/drivers/platform/x86/intel_scu_ipc.c
+++ b/drivers/platform/x86/intel_scu_ipc.c
@@ -148,7 +148,10 @@
 			return -ETIMEDOUT;
 		}
 	}
-	return (status >> 1) & 1;
+	if ((status >> 1) & 1)
+		return -EIO;
+
+	return 0;
 }
 
 /* Read/Write power control(PMIC in Langwell, MSIC in PenWell) registers */