qcacmn: Use appropriate value to define invalid WBM ring

Define INVALID_WBM_RING_NUM with 0xF instead 0xFF. This
limits shifting operation within bound.

Change-Id: I646966d8d50ef4f8b3096a96e1e78fd69a878646
CRs-Fixed: 3187163

dp/wifi3.0/dp_internal.h

@@ -41,7 +41,7 @@
 /* Macro For NYSM value received in VHT TLV */
 #define VHT_SGI_NYSM 3
 
-#define INVALID_WBM_RING_NUM 0xFF
+#define INVALID_WBM_RING_NUM 0xF
 
 /* struct htt_dbgfs_cfg - structure to maintain required htt data
  * @msg_word: htt msg sent to upper layer