ionic: Rate limit unknown xcvr type messages

ionic: Rate limit unknown xcvr type messages

Running ethtool repeatedly with a transceiver unknown to the driver or
firmware will cause the driver to spam the kernel logs with "unknown
xcvr type" messages which can distract from real issues; and this isn't
interesting information outside of debugging. Fix this by rate limiting
the output so that there are still notifications but not so many that
they flood the log.

Using dev_dbg_once() would reduce the number of messages further, but
this would miss the case where a different unknown transceiver type is
plugged in, and its status is requested.

Fixes: 4d03e00a2140 ("ionic: Add initial ethtool support")
Signed-off-by: Eric Joyner <eric.joyner@amd.com>
Reviewed-by: Brett Creeley <brett.creeley@amd.com>
Link: https://patch.msgid.link/20260206224651.1491-1-eric.joyner@amd.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>