mwifiex: get rid of BA setup helper functions

mwifiex: get rid of BA setup helper functions

This patch removes BA setup helper routines
mwifiex_is_bastream_setup and  mwifiex_is_amsdu_in_ampdu_allowed.

Current code will use two functions to check bastream setup and
amsdu in ampdu. This patch change these functions to flags, thus
avoiding redundant spin_lock check while dequeuing TX packets.

Signed-off-by: Zhaoyang Liu <liuzy@marvell.com>
Reviewed-by: Cathy Luo <cluo@marvell.com>
Reviewed-by: Avinash Patil <patila@marvell.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>