net: stmmac: optimization to boot up KPI

Read early ethernet dtsi flag to enable this feature.
Disable autoneg and configure MAC and PHY with 100 Mbps
link speed.
Read MAC addr, IPv4 and IPv6 addresses from kernel cmd
line parameters in order to assign these to ethernet
interface.

Change-Id: Idc29d1bded210e485e78544c82c03c9526efbae3
Acked-by: Abhishek Chauhan <abchauha@qti.qualcomm.com>
Signed-off-by: Sunil Paidimarri <hisunil@codeaurora.org>