qcacld-3.0: Define SLOTS_PER_DATAPATH_TX in common project

Common project be self contained as much as possible.

Change-Id: I9dd3cea3b9b2563960dd5d81a661c9ac1e61ac0d
CRs-Fixed: 1009290

uapi/linux/osapi_linux.h

@@ -231,7 +231,6 @@ void a_netbuf_queue_init(A_NETBUF_QUEUE_T *q);
 #include "ath_carr_pltfrm.h"
 #endif /* QCA_PARTNER_PLATFORM */
 
-#define SLOTS_PER_DATAPATH_TX 2
 #else                           /* __KERNEL__ */
 
 #ifdef __GNUC__