ath10k: remove unused variable 'id' in ath10k_pci_tx_pipe_cleanup()

mete_data is extracted from ce descriptor and stored in variable 'id'.
later, id is not used anywhere in the same function.

Fixes: d84a512d ("ath10k: remove transfer_id from ath10k_hif_cb::tx_completion")

Signed-off-by: Raja Mani <rmani@qti.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>