mwifiex: discard deauth and disassoc event during WPS session

Some GO will send deauth or disassoc packet at the end of WPS
handshake, which causes P2P connecion failure due to the race
condition between event path and data path.

Signed-off-by: Stone Piao <piaoyun@marvell.com>
Signed-off-by: Bing Zhao <bzhao@marvell.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>