netlink: specs: ethtool: fix random typos

Working on the code gen for C reveals typos in the ethtool spec
as the compiler tries to find the names in the existing uAPI
header. Fix the mistakes.

Fixes: a353318e

 ("tools: ynl: populate most of the ethtool spec")
Acked-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/20230605233257.843977-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>