imx6: icorem6: Add ENET support

Add enet support for engicam icorem6 qdl starter kit.
- Add pinmux settings
- Add board_eth_init

TFTP log:
--------
Net:   FEC [PRIME]
Hit any key to stop autoboot:  0
icorem6qdl> tftpboot {fdt_addr} imx6dl-icore.dtb
Using FEC device
TFTP from server 192.168.2.96; our IP address is 192.168.2.75
Filename 'imx6dl-icore.dtb'.
Load address: 0x0
Loading: ######
         1.3 MiB/s
done
Bytes transferred = 28976 (7130 hex)
CACHE: Misaligned operation at range [00000000, 00007130]
icorem6qdl>

Cc: Joe Hershberger <joe.hershberger@ni.com>
Cc: Peng Fan <peng.fan@nxp.com>
Cc: Stefano Babic <sbabic@denx.de>
Cc: Fabio Estevam <fabio.estevam@nxp.com>
Cc: Matteo Lisi <matteo.lisi@engicam.com>
Cc: Michael Trimarchi <michael@amarulasolutions.com>
Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>

include/configs/imx6qdl_icore.h

@@ -111,6 +111,18 @@
 # define CONFIG_SYS_FSL_ESDHC_ADDR	USDHC2_BASE_ADDR
 #endif
 
+/* Ethernet */
+#ifdef CONFIG_FEC_MXC
+# define IMX_FEC_BASE			ENET_BASE_ADDR
+# define CONFIG_FEC_MXC_PHYADDR		0
+# define CONFIG_FEC_XCV_TYPE		RMII
+# define CONFIG_ETHPRIME		"FEC"
+
+# define CONFIG_MII
+# define CONFIG_PHYLIB
+# define CONFIG_PHY_SMSC
+#endif
+
 /* SPL */
 #ifdef CONFIG_SPL
 # define CONFIG_SPL_MMC_SUPPORT