qcacld-3.0: Add an attribute to set wfc state via set wifi config

Currently there is no attribute to set the wifi calling state
from user space to fw.
With this change add an attribute to set wifi config vendor
command to configure wifi calling state to fw via platform
driver.

Change-Id: I982e9a7245b9e5108cd6cbcb4162daa4b4b6a412
CRs-Fixed: 3345705