r8169: remove the firmware of RTL8111D.

The binary file of the firmware is moved to linux-firmware repository.
The firmwares are rtl_nic/rtl8168d-1.fw and rtl_nic/rtl8168d-2.fw.
The driver goes along if the firmware couldn't be found. However, it
is suggested to be done with the suitable firmware.

Some wrong PHY parameters are directly corrected in the driver.

Simple firmware checking added per Ben Hutchings suggestion.

Signed-off-by: Hayes Wang <hayeswang@realtek.com>
Signed-off-by: Francois Romieu <romieu@fr.zoreil.com>
Cc: Ben Hutchings <benh@debian.org>
Signed-off-by: David S. Miller <davem@davemloft.net>