net: txgbe: Distinguish between 40G and 25G devices

For the following patches to support PHYLINK for AML 25G devices,
separate MAC type wx_mac_aml40 to maintain the driver of 40G devices.
Because 40G devices will complete support later, not now.

And this patch makes the 25G devices use some PHYLINK interfaces, but it
is not yet create PHYLINK and cannot be used on its own. It is just
preparation for the next patches.

Signed-off-by: Jiawen Wu <jiawenwu@trustnetic.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/592B1A6920867D0C+20250521064402.22348-4-jiawenwu@trustnetic.com


Signed-off-by: Paolo Abeni <pabeni@redhat.com>