warp7: hab: Set environment variable indicating IVT offset

This patch introduces the environment variable ivt_offset. When we define a
load address for Linux or DTB or any file the IVT associated with that file
is prepended. We extract the actual load addresses from u-boot.cfg and feed
these values into the code-signing process - hence we want u-boot to have
the real load addresses exported in uboot.cfg.

ivt_offset represents the addition or subtraction from the load address
that must happen to find an IVT header.
Signed-off-by: NBryan O'Donoghue <bryan.odonoghue@linaro.org>
Tested-by: NBreno Lima <breno.lima@nxp.com>
Reviewed-by: NFabio Estevam <fabio.estevam@nxp.com>

include/configs/warp7.h

@@ -10,6 +10,7 @@
 #define __WARP7_CONFIG_H
 
 #include "mx7_common.h"
+#include <imximage.h>
 
 #define PHYS_SDRAM_SIZE			SZ_512M
 
@@ -50,6 +51,7 @@
 	"finduuid=part uuid mmc 0:${rootpart} uuid\0" \
 	"mmcargs=setenv bootargs console=${console},${baudrate} " \
 		"root=PARTUUID=${uuid} rootwait rw\0" \
+	"ivt_offset=" __stringify(BOOTROM_IVT_HDR_OFFSET)"\0"\
 	"warp7_auth_or_fail=hab_auth_img_or_fail ${hab_ivt_addr} ${filesize} 0;\0" \
 	"loadbootscript=" \
 		"load mmc ${mmcdev}:${mmcpart} ${loadaddr} ${script};\0" \