mwifiex: remove unused tid_tbl_lock from mwifiex_tid_tbl

mwifiex: remove unused tid_tbl_lock from mwifiex_tid_tbl

ra_list_spinlock is used to protect struct mwifiex_wmm_desc and
embedded structures such as ra_list. tid_tbl_lock while more fine
grained, is not used but in one function. That function is not
called reentrantly. To protect ra_list from concurrent modification
ra_list_spinlock must be held.

Signed-off-by: Andreas Fenkart <[email protected]>
Signed-off-by: Avinash Patil <[email protected]>
Signed-off-by: Bing Zhao <[email protected]>
Signed-off-by: John W. Linville <[email protected]>