mwifiex: correction in status codes used for association failure

When AP responds with appropriate status code, we forward that
code correctly to cfg80211. But sometimes when there is no
response from AP, our firmware uses proprietary status codes.
We will map authentication timeout to WLAN_STATUS_AUTH_TIMEOUT
and other proprietary codes to WLAN_STATUS_UNSPECIFIED_FAILURE.

Signed-off-by: Amitkumar Karwar <akarwar@marvell.com>
Signed-off-by: Bing Zhao <bzhao@marvell.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>