NimBLE host: Make LE data length set API public

* Add public API `ble_gap_set_data_len` to set data length in controller.

Author: prasad-alatkar

nimble/host/include/host/ble_gap.h

@@ -1801,6 +1801,22 @@ int ble_gap_wl_set(const ble_addr_t *addrs, uint8_t white_list_count);
 int ble_gap_update_params(uint16_t conn_handle,
                           const struct ble_gap_upd_params *params);
 
+/**
+ * Configure LE Data Length in controller (OGF = 0x08, OCF = 0x0022).
+ *
+ * @param conn_handle      Connection handle.
+ * @param tx_octets        The preferred value of payload octets that the Controller
+ *                         should use for a new connection (Range
+ *                         0x001B-0x00FB).
+ * @param tx_time          The preferred maximum number of microseconds that the local Controller
+ *                         should use to transmit a single link layer packet
+ *                         (Range 0x0148-0x4290).
+ *
+ * @return                 0 on success,
+ *                         other error code on failure.
+ */
+int ble_gap_set_data_len(uint16_t conn_handle, uint16_t tx_octets, uint16_t tx_time);
+
 /**
  * Initiates the GAP security procedure.
  *

nimble/host/src/ble_gap.c

@@ -5535,6 +5535,11 @@ ble_gap_update_params(uint16_t conn_handle,
 #endif
 }
 
+int ble_gap_set_data_len(uint16_t conn_handle, uint16_t tx_octets, uint16_t tx_time)
+{
+    return ble_hs_hci_util_set_data_len(conn_handle, tx_octets, tx_time);
+}
+
 /*****************************************************************************
  * $security                                                                 *
  *****************************************************************************/