net:nfc:digital: Fix a double free in digital_tg_recv_dep_req

net:nfc:digital: Fix a double free in digital_tg_recv_dep_req

BugLink: https://bugs.launchpad.net/bugs/1929455
[ Upstream commit 75258586793efc521e5dd52a5bf6c7a4cf7002be ]

In digital_tg_recv_dep_req, it calls nfc_tm_data_received(..,resp).
If nfc_tm_data_received() failed, the callee will free the resp via
kfree_skb() and return error. But in the exit branch, the resp
will be freed again.

My patch sets resp to NULL if nfc_tm_data_received() failed, to
avoid the double free.

Fixes: 1c7a4c24fbfd9 ("NFC Digital: Add target NFC-DEP support")
Signed-off-by: Lv Yunlong <lyl2019@mail.ustc.edu.cn>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Kelsey Skunberg <kelsey.skunberg@canonical.com>