docs: net: ena: Fix ena_start_xmit() function name typo

The ena.rst documentation referred to end_start_xmit() when it should refer
to ena_start_xmit(). Fix the typo.

Signed-off-by: Zenghui Yu <yuzenghui@huawei.com>
Acked-by: Shay Agroskin <shayagr@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/networking/device_drivers/ethernet/amazon/ena.rst

@@ -267,7 +267,7 @@ DATA PATH
 Tx
 --
 
-end_start_xmit() is called by the stack. This function does the following:
+ena_start_xmit() is called by the stack. This function does the following:
 
 - Maps data buffers (skb->data and frags).
 - Populates ena_buf for the push buffer (if the driver and device are