nimble: Allow to define offset for HCI VS commands

This allows to tune starting offset for NimBLE VS HCI commands.

nimble/include/nimble/hci_common.h

@@ -1063,7 +1063,7 @@ struct ble_hci_le_set_host_feat_cp {
 
 /* --- Vendor specific commands (OGF 0x003F) */
 /* Read Random Static Address */
-#define BLE_HCI_OCF_VS_RD_STATIC_ADDR                   (0x0001)
+#define BLE_HCI_OCF_VS_RD_STATIC_ADDR                   (MYNEWT_VAL(BLE_HCI_VS_OCF_OFFSET) + (0x0001))
 struct ble_hci_vs_rd_static_addr_rp {
     uint8_t addr[6];
 } __attribute__((packed));
@@ -1071,7 +1071,7 @@ struct ble_hci_vs_rd_static_addr_rp {
 /* Set default transmit power. Actual selected TX power is returned
  * in reply. Setting 0xff restores controller reset default.
  */
-#define BLE_HCI_OCF_VS_SET_TX_PWR                       (0x0002)
+#define BLE_HCI_OCF_VS_SET_TX_PWR                       (MYNEWT_VAL(BLE_HCI_VS_OCF_OFFSET) + (0x0002))
 struct ble_hci_vs_set_tx_pwr_cp {
     int8_t tx_power;
 } __attribute__((packed));

nimble/syscfg.yml

@@ -101,6 +101,13 @@ syscfg.defs:
             Enables support for NimBLE specific vendor HCI commands
         value: 0
 
+    BLE_HCI_VS_OCF_OFFSET:
+        description: >
+            This defines starting offset for NimBLE specific vendor HCI commands.
+            Purpose of this is to improve compatibility with other custom
+            implementations.
+        value: 0
+
 # Allow periodic sync transfer only if 5.1 or higher
 syscfg.restrictions:
     - "'BLE_PERIODIC_ADV_SYNC_TRANSFER == 0' || 'BLE_VERSION >= 51'"