mwifiex: make tos_to_tid_inv part of mwifiex_private structure

mwifiex: make tos_to_tid_inv part of mwifiex_private structure

tos_to_tid_inv values are needed even during TDLS restore
operations. Currently tos_to_tid_inv is part of wmm.c and
is declared static.
Make it part of private structure so that it can be used in
other files as well.

Signed-off-by: Avinash Patil <patila@marvell.com>
Signed-off-by: Bing Zhao <bzhao@marvell.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>