UPSTREAM: net/packet: fix overflow in check for tp_reserve

When calculating po->tp_hdrlen + po->tp_reserve the result can overflow.

Fix by checking that tp_reserve <= INT_MAX on assign.

Bug: 36725304
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
(cherry picked from commit bcc5364bdcfe131e6379363f089e7b4108d35b70)

Change-Id: I17af0b50ea5b1caa8349e216b88ef57f5287de3c