cbfs: Move result variable into the struct

Move the result variable into the struct also, so that it can be used when
BSS is not available. Add a function to read it.

Note that all functions sill use the BSS version of the data.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Tested-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/cmd/cbfs.c b/cmd/cbfs.c
index 3d1fc95..98e652a 100644
--- a/cmd/cbfs.c
+++ b/cmd/cbfs.c
@@ -29,7 +29,7 @@
 		}
 	}
 	file_cbfs_init(end_of_rom);
-	if (file_cbfs_result != CBFS_SUCCESS) {
+	if (cbfs_get_result() != CBFS_SUCCESS) {
 		printf("%s.\n", file_cbfs_error());
 		return 1;
 	}
@@ -67,7 +67,7 @@
 
 	file = file_cbfs_find(argv[2]);
 	if (!file) {
-		if (file_cbfs_result == CBFS_FILE_NOT_FOUND)
+		if (cbfs_get_result() == CBFS_FILE_NOT_FOUND)
 			printf("%s: %s\n", file_cbfs_error(), argv[2]);
 		else
 			printf("%s.\n", file_cbfs_error());