tid_data is assigned but never read, hence it is redundant
and can be removed. Cleans up clang warning:

drivers/net/wireless/realtek/rtlwifi/base.c:1581:2: warning: Value
stored to 'tid_data' is never read
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>