wlan: Don't decrease no of sessions if no of session is zero.

If due to some reason wlan_hdd_decr_active_session
is being called when active sessions are zero;
wlan_hdd_decr_active_session will make active sessions
as 255. Next time driver will not be able to connect
as no of connected sessions will be 255.
Fix is to Don't decrease no of sessions if no of session is
zero.

CRs-Fixed: 704947
Change-Id: I29b5112b042b84872d243b53ba5b912e4823a41f
1 file changed
tree: d3989f5541b75968f58eb998678af62138ff34cc
  1. CORE/
  2. firmware_bin/
  3. riva/
  4. Android.mk
  5. Kbuild
  6. Kconfig
  7. Makefile