Merge branch 'net-renesas-rswitch-add-speed-change-support'

Yoshihiro Shimoda says:

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net: renesas: rswitch: Add speed change support

Add speed change support at runtime for the latest SoC version.
Also, add ethtool .[gs]et_link_ksettings.

v1: https://lore.kernel.org/all/20230803120621.1471440-1-yoshihiro.shimoda.uh@renesas.com/
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Link: https://lore.kernel.org/r/20230807003231.1552062-1-yoshihiro.shimoda.uh@renesas.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>