BlockVariable: flush variable twice

If it's the last flush operation, variable may not be flushed into the
block device. So flush it twice. It could make sure that everything is
flushed into block device.

Signed-off-by: Haojian Zhuang <haojian.zhuang@linaro.org>

HisiPkg/HiKeyPkg/Drivers/BlockVariableDxe/BlockVariableDxe.c

@@ -176,6 +176,14 @@ FvbWrite (
     DEBUG ((EFI_D_ERROR, "FvbWrite StartLba:%x, Lba:%x, Offset:%x, Status:%x\n",
             Instance->StartLba, Lba, Offset, Status));
   }
+  // Sometimes the variable isn't flushed into block device if it's the last flush operation.
+  // So flush it again.
+  Status = BlockIo->WriteBlocks (BlockIo, BlockIo->Media->MediaId, Instance->StartLba + Lba,
+                                 Bytes, DataPtr);
+  if (EFI_ERROR (Status)) {
+    DEBUG ((EFI_D_ERROR, "FvbWrite StartLba:%x, Lba:%x, Offset:%x, Status:%x\n",
+            Instance->StartLba, Lba, Offset, Status));
+  }
 exit:
   FreePool (DataPtr);
   return Status;