imximage: fix size of image to load.

sbuf->st_size already includes sizeof(struct imx_header),
so remove extra addition.

Signed-off-by: Troy Kisky <troy.kisky@boundarydevices.com>
diff --git a/tools/imximage.c b/tools/imximage.c
index 3e9ee6a..7dbf36c 100644
--- a/tools/imximage.c
+++ b/tools/imximage.c
@@ -221,8 +221,7 @@
 
 	/* The external flash header must be at the end of the DCD table */
 	dcd_v1->addr_data[dcd_len].type = sbuf->st_size +
-				imxhdr->flash_offset +
-				sizeof(struct imx_header);
+				imxhdr->flash_offset;
 
 	/* Security feature are not supported */
 	fhdr_v1->app_code_csf = 0;
@@ -253,8 +252,7 @@
 
 	hdr_v2->boot_data.start = fhdr_v2->self - imxhdr->flash_offset;
 	hdr_v2->boot_data.size = sbuf->st_size +
-			imxhdr->flash_offset +
-			sizeof(struct imx_header);
+			imxhdr->flash_offset;
 
 	/* Security feature are not supported */
 	fhdr_v2->csf = 0;