re-orgnize code, Multi-TX feature added.

1. code are re-orgnized, abstract layer is removed. struct alx_hw is removed.
2. Multi-TX feature is added since the HW have 4 tx-Qs.
3. Interrupt usage for MSIX for RSS/Multi-TX is revised to share vector to
   save system resources.
   Interrupt allocation is moved to .probe routine.
4. Extension PHY resgister access is added as well.

please NOTE, this version of code just pass compiler (under net-next.git env),
 only load/unload test is done. any other network related functions are not
tested yet.

BTW, when I run checkpatch on this code, there are many warnings about:

WARNING: networking block comments put the trailing */ on a separate line

there are also many many same warnings when I run it on other drivers in the
kernel such as broadcom/tg3, intel/igbe

Signed-off-by: xiong <xiong@qca.qualcomm.com>
Signed-off-by: Luis R. Rodriguez <mcgrof@do-not-panic.com>