'params' is allocated in digital_tg_listen_mdaa(), but not free when
digital_send_cmd() failed, which will cause memory leak. Fix it by
freeing 'params' if digital_send_cmd() return failed.

Fixes: 1c7a4c24 ("NFC Digital: Add target NFC-DEP support")
Signed-off-by: Ziyang Xuan <william.xuanziyang@huawei.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>