fix: net: skb: introduce kfree_skb_reason() (v5.15.58..v5.16)

fix: net: skb: introduce kfree_skb_reason() (v5.15.58..v5.16)

See upstream commit :

  commit c504e5c2f9648a1e5c2be01e8c3f59d394192bd3
  Author: Menglong Dong <imagedong@tencent.com>
  Date:   Sun Jan 9 14:36:26 2022 +0800

    net: skb: introduce kfree_skb_reason()

    Introduce the interface kfree_skb_reason(), which is able to pass
    the reason why the skb is dropped to 'kfree_skb' tracepoint.

    Add the 'reason' field to 'trace_kfree_skb', therefor user can get
    more detail information about abnormal skb with 'drop_monitor' or
    eBPF.

    All drop reasons are defined in the enum 'skb_drop_reason', and
    they will be print as string in 'kfree_skb' tracepoint in format
    of 'reason: XXX'.

    ( Maybe the reasons should be defined in a uapi header file, so that
    user space can use them? )

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: Ib3c039207739dad10f097cf76474e0822e351273