Revert "mhi: Fix networking tree build."

This reverts commit 40e15940.

Looks like this commit breaks the build for me.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

include/linux/mhi.h

@@ -719,13 +719,8 @@ void mhi_device_put(struct mhi_device *mhi_dev);
  *                            host and device execution environments match and
  *                            channels are in a DISABLED state.
  * @mhi_dev: Device associated with the channels
- * @flags: MHI channel flags
  */
-int mhi_prepare_for_transfer(struct mhi_device *mhi_dev,
-			     unsigned int flags);
-
-/* Automatically allocate and queue inbound buffers */
-#define MHI_CH_INBOUND_ALLOC_BUFS BIT(0)
+int mhi_prepare_for_transfer(struct mhi_device *mhi_dev);
 
 /**
  * mhi_unprepare_from_transfer - Reset UL and DL channels for data transfer.