Consider the followed case that the user change speed and reset the net
interface. Before the hw change speed successfully, the driver get old
old speed from hw by timer task. After reset, the previous speed is config
to hw. As a result, the new speed is configed successfully but lost after
PF reset. The followed pictured shows more dirrectly.

+------+              +----+                 +----+
| USER |              | PF |                 | HW |
+---+--+              +-+--+                 +-+--+
    |  ethtool -s 100G  |                      |
    +------------------>|   set speed 100G     |
    |                   +--------------------->|
    |                   |  set successfully    |
    |                   |<---------------------+---+
    |                   |query cfg (timer task)|   |
    |                   +--------------------->|   | handle speed
    |                   |     return 200G      |   | changing event
    |  ethtool --reset  |<---------------------+   | (100G)
    +------------------>|  cfg previous speed  |<--+
    |                   |  after reset (200G)  |
    |                   +--------------------->|
    |                   |                      +---+
    |                   |query cfg (timer task)|   |
    |                   +--------------------->|   | handle speed
    |                   |     return 100G      |   | changing event
    |                   |<---------------------+   | (200G)
    |                   |                      |<--+
    |                   |query cfg (timer task)|
    |                   +--------------------->|
    |                   |     return 200G      |
    |                   |<---------------------+
    |                   |                      |
    v                   v                      v

This patch save new speed if hw change speed successfully, which will be
used after reset successfully.

Fixes: 2d03eacc ("net: hns3: Only update mac configuation when necessary")
Signed-off-by: Peiyang Wang <wangpeiyang1@huawei.com>
Signed-off-by: Jijie Shao <shaojijie@huawei.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>