Revert "neighbour: fix unaligned access to pneigh_entry"

This reverts commit 9fcc3c3d26a049aa04e0bc0462f84a9a775f428e which is
commit ed779fe4c9b5a20b4ab4fd6f3e19807445bb78c7 upstream.

It breaks the Android kernel abi and is not needed for Android systems,
so it is safe to revert.

Bug: 161946584
Change-Id: I0aa37ddcb0939b55d0d1b74ab3e0432b02cc5285
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
diff --git a/include/net/neighbour.h b/include/net/neighbour.h
index 6709365..7750ef0 100644
--- a/include/net/neighbour.h
+++ b/include/net/neighbour.h
@@ -180,7 +180,7 @@
 	struct net_device	*dev;
 	u8			flags;
 	u8			protocol;
-	u32			key[];
+	u8			key[];
 };
 
 /*