lib: net_buf: remove deprecated zephyr/net/buf.h header file

Remove the deprecated zephyr/net/buf.h header file.

Signed-off-by: Henrik Brix Andersen <hebad@vestas.com>

MAINTAINERS.yml

@@ -2875,7 +2875,6 @@ Networking:
     - include/zephyr/net/ieee802154*.h
     - include/zephyr/net/ptp.h
     - include/zephyr/net/wifi*.h
-    - include/zephyr/net/buf.h
     - include/zephyr/net/dhcpv4*.h
     - include/zephyr/net/http/
     - samples/net/gptp/
@@ -2928,7 +2927,6 @@ Networking:
     - jukkar
   files:
     - doc/services/net_buf/
-    - include/zephyr/net/buf.h
     - include/zephyr/net_buf.h
     - lib/net_buf/
     - tests/lib/net_buf/

doc/releases/migration-guide-4.0.rst

@@ -505,7 +505,7 @@ Networking
   will take network interface pointer as a first parameter. (:github:`77987`)
 
 * To facilitate use outside of the networking subsystem, the network buffer header file was renamed
-  from :zephyr_file:`include/zephyr/net/buf.h` to :zephyr_file:`include/zephyr/net_buf.h` and the
+  from ``include/zephyr/net/buf.h`` to :zephyr_file:`include/zephyr/net_buf.h` and the
   implementation moved to :zephyr_file:`lib/net_buf/`. (:github:`78009`)
 
 * The ``work_q`` parameter to ``NET_SOCKET_SERVICE_SYNC_DEFINE`` and

include/zephyr/net/buf.h

@@ -1,14 +0,0 @@
-/*
- * Copyright (c) 2015 Intel Corporation
- *
- * SPDX-License-Identifier: Apache-2.0
- */
-
-#ifndef ZEPHYR_INCLUDE_NET_BUF_DEPRECATED_H_
-#define ZEPHYR_INCLUDE_NET_BUF_DEPRECATED_H_
-
-#include <zephyr/net_buf.h>
-
-#warning This header is deprecated, include <zephyr/net_buf.h> instead
-
-#endif /*  ZEPHYR_INCLUDE_NET_BUF_DEPRECATED_H_ */