imx: add i.MX6ULZ board

Add i.MX6ULZ board support. the i.MX6ULZ is SW compatible
with i.MX6ULL. so most code of i.MX6ULL can be reused
by i.MX6ULZ.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Reviewed-by: Ye Li <ye.li@nxp.com>
Reviewed-by: Fabio Estevam <festevam@gmail.com>
diff --git a/include/configs/mx6ullevk.h b/include/configs/mx6ullevk.h
index 1fc5c24..f5f3de6 100644
--- a/include/configs/mx6ullevk.h
+++ b/include/configs/mx6ullevk.h
@@ -55,7 +55,7 @@
 	"console=ttymxc0\0" \
 	"fdt_high=0xffffffff\0" \
 	"initrd_high=0xffffffff\0" \
-	"fdt_file=imx6ull-14x14-evk.dtb\0" \
+	"fdt_file=undefined\0" \
 	"fdt_addr=0x83000000\0" \
 	"boot_fdt=try\0" \
 	"ip_dyn=yes\0" \
@@ -87,6 +87,16 @@
 		"else " \
 			"bootz; " \
 		"fi;\0" \
+		"findfdt="\
+			"if test $fdt_file = undefined; then " \
+				"if test $board_name = ULZ-EVK && test $board_rev = 14X14; then " \
+					"setenv fdt_file imx6ulz-14x14-evk.dtb; fi; " \
+				"if test $board_name = EVK && test $board_rev = 14X14; then " \
+					"setenv fdt_file imx6ull-14x14-evk.dtb; fi; " \
+				"if test $fdt_file = undefined; then " \
+					"echo WARNING: Could not determine dtb to use; " \
+				"fi; " \
+			"fi;\0" \
 	"netargs=setenv bootargs console=${console},${baudrate} " \
 		"root=/dev/nfs " \
 	"ip=dhcp nfsroot=${serverip}:${nfsroot},v3,tcp\0" \
@@ -113,6 +123,7 @@
 		"fi;\0" \
 
 #define CONFIG_BOOTCOMMAND \
+	   "run findfdt;" \
 	   "mmc dev ${mmcdev};" \
 	   "mmc dev ${mmcdev}; if mmc rescan; then " \
 		   "if run loadbootscript; then " \