ARM: omap2plus_defconfig: Enable support for davinci_emac

We have this on at least 3517-evm and dm8168-evm. Let's
enable davinci_emac so those can be booted with NFSroot.

Cc: Brian Hutchinson <b.hutchman@gmail.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/configs/omap2plus_defconfig

@@ -145,6 +145,7 @@ CONFIG_KS8851_MLL=y
 CONFIG_SMC91X=y
 CONFIG_SMSC911X=y
 # CONFIG_NET_VENDOR_STMICRO is not set
+CONFIG_TI_DAVINCI_EMAC=y
 CONFIG_TI_CPSW=y
 # CONFIG_NET_VENDOR_VIA is not set
 # CONFIG_NET_VENDOR_WIZNET is not set