ath10k: fix compilation warning

This change fixes below compilation warning.

smatch warnings:
 drivers/net/wireless/ath/ath10k/mac.c:9125 ath10k_mac_op_set_tid_config() error: uninitialized symbol 'ret'.

No functional changes. Compile tested only.

Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Tamizh Chelvam <tamizhr@codeaurora.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/1604507837-29361-1-git-send-email-tamizhr@codeaurora.org