HSD #16020988342: net: stmmac: xgmac: Add FPE link partner hand-shaking support

commit 1efb1ba7a595dbaa23a5576a656bb8f9b47ed01a from
https://github.com/altera-opensource/linux-socfpga.git

 socfpga-6.1.55-lts.

In order to discover whether remote station supports frame preemption, local
station sends verify mPacket and expects response mPacket in return from the
remote station.

Commit 5a558611 (net: stmmac: support FPE link partner hand-shaking procedure)
added same support for dwmac4. Added the support for xgmac also.

Signed-off-by: G Thomas, Rohan <rohan.g.thomas@intel.com>
Signed-off-by: Liwei Song <liwei.song@windriver.com>