drivers/net/r8168: Add driver for realtek nic

One thing that is vital to this patch is the MAC address setting
in case the EEPROM/efuse is unconfigured.
Linux now recognises the default MAC address on GA-G41M-ES2L which
does rely on the default bios settings for the MAC address.

Change-Id: I32e070b545b4c6369686a7087b7ff838d00764e3
Signed-off-by: Damien Zammit <damien@zamaudio.com>
Reviewed-on: https://review.coreboot.org/14927
Tested-by: build bot (Jenkins)
Reviewed-by: Martin Roth <martinroth@google.com>
diff --git a/src/drivers/net/Kconfig b/src/drivers/net/Kconfig
new file mode 100644
index 0000000..b4bafd2
--- /dev/null
+++ b/src/drivers/net/Kconfig
@@ -0,0 +1,5 @@
+config REALTEK_8168_RESET
+	bool "Realtek 8168 reset"
+	help
+	  This forces a realtek 10ec:8168 card to reset to ensure power state
+	  is correct at boot.