ath6kl: sme_state shortcut to SME_DISCONNECTED removed

When an NL80211_DISCONNECT is sent to cfg80211, the driver's cfg80211
disconnect function sets the sme_state to SME_DISCONNECTED before receiving
a WMI_DISCONNECT_EVENT from the firmware.  This caused cfg80211 to not know
that the connection is disconnected because the driver fails to notify
cfg80211 upon receiving WMI_DISCONNECT_EVENT from the firmware believing
it is already disconnected.

Signed-off-by: Dan Kephart <dan.kephart@lairdtech.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>