net: emaclite: update reset_lock member documentation

Instead of generic description, mention what reset_lock actually
protects i.e. lock to serialize xmit and tx_timeout execution.
Signed-off-by: NRadhey Shyam Pandey <radhey.shyam.pandey@amd.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/xilinx/xilinx_emaclite.c

@@ -108,7 +108,7 @@
  * @next_tx_buf_to_use:	next Tx buffer to write to
  * @next_rx_buf_to_use:	next Rx buffer to read from
  * @base_addr:		base address of the Emaclite device
- * @reset_lock:		lock used for synchronization
+ * @reset_lock:		lock to serialize xmit and tx_timeout execution
  * @deferred_skb:	holds an skb (for transmission at a later time) when the
  *			Tx buffer is not free
  * @phy_dev:		pointer to the PHY device