qcacmn: Set lock_cookie_freelist as NULL in qdf_lock_stats_deinit

lock_cookie_freelist is global static, which means it is set as NULL when
loading driver module. It works well when there is only one driver module.
For the CE platform with CONFIG_WLAN_RESIDENT_DRIVER defined, driver is
split into two modules, one module keeps variables and functions in
kernel, the other module is used to trigger rmmod/insmod function. In this
case, lock_cookie_freelist is not NULL when insmod is triggered the second
time through the second module.

Set lock_cookie_freelist as NULL in qdf_lock_stats_deinit.

Change-Id: Ia20fcc230c3a43eed9b646689348ad37b77811f2
CRs-Fixed: 2742118

qdf/linux/src/qdf_lock.c

@@ -830,6 +830,7 @@ void qdf_lock_stats_deinit(void)
 				  __func__, lock_cookies[i].u.cookie.func,
 				  lock_cookies[i].u.cookie.line);
 	}
+	lock_cookie_freelist = NULL;
 }
 
 /* allocated separate memory in case the lock memory is freed without