ethernet: sun: Fix spelling mistake "mis-matched" -> "mismatched"

There is a spelling mistake in a dev_err message. Fix it.

Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Link: https://lore.kernel.org/r/20220316234620.55885-1-colin.i.king@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>