qcacld-3.0: Remove CSR_ROAM_SESSION_MAX

As part of the effort to use a single definition for the maximum number
of vdevs, replace CSR_ROAM_SESSION_MAX with WLAN_MAX_VDEVS.

Change-Id: I71f9c02acec23314f65ac9d5ee3401ed7b4af580
CRs-Fixed: 2393166
12 files changed