Realtek 8168 rom size

[Gelip]

I think that in the current version of the master is not enough to remove the config and menu command. About a year ago I helped fix a few bugs in the driver RTL8139 iPXE - DHCP timeout from Realtek 8139 card

[realtek] Allow reaction time between writing RTL_CAPR and reading RTL_CR
[realtek] Ensure EEPROM writes reach chip before starting udelay()
[realtek] Fix reopening of legacy-mode 8139 NIC

Please use iPXE version e411 or 0036 or commit 5d3d62d in linux machine + disable some features in src/config/general.h file to reduce size rom image for NIC Realtek :-)