wlan: Validate hdd context in hdd open and hdd hostapd open apis

Currently hdd open and hdd hostapd open apis does not
validate hdd context because of which there is a possibility that
these apis may end up using invalid hdd context which may lead to
undefined behavior.

To address above issue add a check to validate hdd context in hdd
open and hdd hostapd open apis.

Change-Id: Ia5bdd67e695b2f46ce798b8ca965a68004439c11
CRs-Fixed: 2809493