Return status of the wlan_mlme_get_sta_ch_width is always
returning error resulting in caller not updating with
the phymode correct the vdev object.
When the kernel is querying phymode via cfg80211_get_channel driver is
returning invalid bandwidth post roam resulting in kernel warning.
Fix this by returning proper status in wlan_mlme_get_sta_ch_width
CRs-Fixed: 3641158
Change-Id: I013f75a3e06768127ffc72776eef6885633e927a
cc3e7e51d8