mxssb: Rename image processing function

Rename the functions to better match their purpose. This will come
helpful when implementing image verification.
Signed-off-by: Marek Vasut <marex@denx.de>

mxssb.c

@@ -264,7 +264,7 @@ static void sb_encrypt_tag(struct sb_image_ctx *ictx,
 	EVP_DigestUpdate(md_ctx, &cctx->c_payload, sizeof(*cmd));
 }
 
-static int sb_create_image(struct sb_image_ctx *ictx)
+static int sb_encrypt_image(struct sb_image_ctx *ictx)
 {
 	/* Start image-wide crypto. */
 	EVP_MD_CTX_init(&ictx->md_ctx);
@@ -336,7 +336,7 @@ static int sb_create_image(struct sb_image_ctx *ictx)
 
 char *output_filename = NULL;
 
-static int sb_assemble_image(struct sb_image_ctx *ictx)
+static int sb_write_image(struct sb_image_ctx *ictx)
 {
 	struct sb_boot_image_header *sb_header = &ictx->payload;
 	struct sb_section_ctx *sctx;
@@ -1306,7 +1306,7 @@ err_open:
 
 }
 
-static int sb_parse_image(struct sb_image_ctx *ictx)
+static int sb_build_tree_from_cfg(struct sb_image_ctx *ictx)
 {
 	int ret;
 
@@ -1402,13 +1402,13 @@ int main(int argc, char **argv)
 		return -EINVAL;
 	}
 
-	ret = sb_parse_image(&ctx);
+	ret = sb_build_tree_from_cfg(&ctx);
 	if (ret)
 		goto fail;
 
-	ret = sb_create_image(&ctx);
+	ret = sb_encrypt_image(&ctx);
 	if (!ret)
-		ret = sb_assemble_image(&ctx);
+		ret = sb_write_image(&ctx);
 
 fail:
 	sb_free_image(&ctx);