wlan: Do not allow more than one SAP interface at a time

User is able to add multiple instances of SAP via IOCTL using
"iwpriv wlan0 initAP".

If SAP interface with name "softap.0" already exists, ignore
the add interface request.
In add SAP interface, name and other configurations are not
passed by user as part of IOCTL, so no need to delete the old
interface and create a new one.

Change-Id: If072b5b50cbaaa053f015776b78cf42fe5f35df1
CRs-Fixed: 612331
wlan: Change memcpy to vos_mem_copy.

Change memcpy to vos_mem_cpy (use VOS mem API wrappers)
so as to centralise the change of memcpy to the safe
memory copy function.

Change-Id: I153c34a8931d1701ba22fa80964b35f43df5ea52
CRs-Fixed:  614143
wlan: disable 11d scan which is done after driver is loaded

For drivers supporting the enhanced regulatory feature the
initial 11d scan is not required, because such drivers are
configured with the world roaming SKUs so that they do not
violate the restrictions imposed by the regulatory
authorities.

Change-Id: I85ff3933c69439be14a1f8e7b7256ad6cd32e12e
CRs-Fixed: 568968
wlan: Release 3.2.3.244

Revision 3.2.3.244