add infineon adm6996fc support on etherswitch

[yamori813_yahoo.co.jp]

Summary

add infineon adm6996fc support on etherswitch

Test Plan

check on Netgear WGR614Cv7

[mizhka]

1. I see some "magic" constants. May be worth to add macros.
2. DPRINTF usage: it prints function name on each call, is it useful/enough useful?
3. "style(9)": ADM6996FC_READREG/WRITEREG - to be tab instead of space
4. No checks on malloc results, may be NULL.
5. Probe: can you add array of IDs to match. In future it will be easy to add IDs into array to bring support of another models.

sys/dev/etherswitch/infineon/adm6996fc.c

722–723

one empty line is enough ;)

[yamori813_yahoo.co.jp]

• review refict

[yamori813_yahoo.co.jp]

• add empty line

[yamori813_yahoo.co.jp]

1. add more macros.

2 This code is same as other ehterswitch code.

3. add space.
4. Other etherswitch code not check malloc also...
5. Check only Product Code.