imx: ventana: config: use bootdir env var for directory of fdt files

In order to make the default boot scripts more flexible, use the variable
'bootdir' to specify the filesystem directory to look for fdt files in.

Signed-off-by: Tim Harvey <tharvey@gateworks.com>

include/configs/gw_ventana.h

@@ -291,14 +291,14 @@
 		"fdt addr ${fdt_addr}\0" \
 	"bootdir=boot\0" \
 	"loadfdt=" \
-		"if ${fsload} ${fdt_addr} boot/${fdt_file}; then " \
-			"echo Loaded DTB from boot/${fdt_file}; " \
+		"if ${fsload} ${fdt_addr} ${bootdir}/${fdt_file}; then " \
+			"echo Loaded DTB from ${bootdir}/${fdt_file}; " \
 			"run fixfdt; " \
-		"elif ${fsload} ${fdt_addr} boot/${fdt_file1}; then " \
-			"echo Loaded DTB from boot/${fdt_file1}; " \
+		"elif ${fsload} ${fdt_addr} ${bootdir}/${fdt_file1}; then " \
+			"echo Loaded DTB from ${bootdir}/${fdt_file1}; " \
 			"run fixfdt; " \
-		"elif ${fsload} ${fdt_addr} boot/${fdt_file2}; then " \
-			"echo Loaded DTB from boot/${fdt_file2}; " \
+		"elif ${fsload} ${fdt_addr} ${bootdir}/${fdt_file2}; then " \
+			"echo Loaded DTB from ${bootdir}/${fdt_file2}; " \
 			"run fixfdt; " \
 		"fi\0" \
 	\