mwifiex: correct paused tx data packet counter

This patch fixes observed issues while updating counter for
number of paused data packets in wmm queue when trying to
delete packet or delete station entry.

Signed-off-by: Zhaoyang Liu <liuzy@marvell.com>
Signed-off-by: Amitkumar Karwar <akarwar@marvell.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>