[etherswitch] add infineon adm6996fc support on etherswitch
This is Infineon ADM6996FC/M/MX driver code on etherswitch framework.
Support PORT and DOT1Q VLAN.
This code suppose ADM6996FC SDC/SDIO connect to SOC network interface
This code tested on Netgear WGR614Cv7.
Submitted by: Hiroki Mori <firstname.lastname@example.org>
Reviewed by: adrian, mizhka
Approved by: adrian(mentor)
Differential Revision: https://reviews.freebsd.org/D8495