warp7: Modify fdt_file environment variable

Use imx7s-warp.dts as fdt_file because this is the name that upstream
kernel will deploy.

Signed-off-by: Breno Lima <breno.lima@nxp.com>
Acked-by: Fabio Estevam <fabio.estevam@nxp.com>

include/configs/warp7.h

@@ -39,7 +39,7 @@
 	"console=ttymxc0\0" \
 	"fdt_high=0xffffffff\0" \
 	"initrd_high=0xffffffff\0" \
-	"fdt_file=imx7d-warp.dtb\0" \
+	"fdt_file=imx7s-warp.dtb\0" \
 	"fdt_addr=0x83000000\0" \
 	"boot_fdt=try\0" \
 	"ip_dyn=yes\0" \