net: restore alpha order to Ethernet devices in config

The displayed list of Ethernet devices in make menuconfig
has gotten out of order. This is mostly due to changes in vendor
names etc, but also because of new Microsoft entry in wrong place.

This restores so that the display is in order even if the names
of the sub directories are not.

Fixes: ca9c54d2

 ("net: mana: Add a driver for Microsoft Azure Network Adapter (MANA)")
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: David S. Miller <davem@davemloft.net>