nimble/host: Modify Advertising Tx power levels

Spec ver 5.4 , Vol 4, Part E, section 7.8.6 mentions the range value for
Tx power level.

Different BLE spec version have modified the range values that Tx Power level
can have. Update the min / max macros to reflect the same

nimble/include/nimble/hci_common.h

@@ -1428,8 +1428,17 @@ struct ble_hci_vs_set_local_irk_cp {
 #define BLE_HCI_ADV_PEER_ADDR_MAX           (1)
 
 /* --- LE advertising channel tx power (OCF 0x0007) */
-#define BLE_HCI_ADV_CHAN_TXPWR_MIN             (-20)
-#define BLE_HCI_ADV_CHAN_TXPWR_MAX             (10)
+#if MYNEWT_VAL(BLE_VERSION) == 50
+#define BLE_HCI_ADV_CHAN_TXPWR_MIN          (-20)
+#define BLE_HCI_ADV_CHAN_TXPWR_MAX          (10)
+#elif MYNEWT_VAL(BLE_VERSION) == 51
+#define BLE_HCI_ADV_CHAN_TXPWR_MIN          (-20)
+#define BLE_HCI_ADV_CHAN_TXPWR_MAX          (20)
+#elif MYNEWT_VAL(BLE_VERSION) >= 52
+#define BLE_HCI_ADV_CHAN_TXPWR_MIN          (-127)
+#define BLE_HCI_ADV_CHAN_TXPWR_MAX          (20)
+#endif
+
 
 /* --- LE set scan enable (OCF 0x000c) */