Ensure data length extension is performed correctly in nimble 1.6

Author: h2zero

cores/nRF5/nimble_config/ext_nimble_config.h

@@ -96,3 +96,8 @@ MYNEWT_VAL_MCU_TARGET__nRF5340_NET
 #endif
 
 #define CONFIG_BT_NIMBLE_LEGACY_VHCI_ENABLE 1
+
+/* FIX DLE with Nimble core 1.6 */
+#if MYNEWT_VAL_BLE_LL_CFG_FEAT_LE_CODED_PHY
+#define BLE_50_FEATURE_SUPPORT 1
+#endif