qcacld-3.0: Remove macro MAX_RATES

Change I05ccc13d1b658e62b19a389e6a480707b5c446b9 ("qcacld-3.0:
Remove wext support for scan commands") removed the usage of
macro MAX_RATES. Since it is unused, remove it.

Change-Id: I3c15363a7ac8f82354bafefb82b14eb83ff6666d
CRs-Fixed: 2378313

core/hdd/src/wlan_hdd_scan.c

@@ -50,8 +50,6 @@
 #include "wlan_hdd_object_manager.h"
 #include "nan_ucfg_api.h"
 
-#define MAX_RATES                       12
-
 #define SCAN_DONE_EVENT_BUF_SIZE 4096
 #define RATE_MASK 0x7f