qcacld-3.0: Remove hdd_max_sta_vdev_count_reached() prototype
The function hdd_max_sta_vdev_count_reached() was removed by:
qcacld-3.0: Check for max allowed STA vdevs in hdd_start_adapter()
Change-Id I5b2dd09fb58aa3135743a029889e689729bd05a7
However, the prototype was not removed, so remove it now.
Change-Id: I3ca75963bb69f0d2fc5a27687566e70b11f02058
CRs-Fixed: 3428740