cbfs: Return the error code from file_cbfs_init()

We may as well return the error code and use it directly in the command
code. CBFS still uses its own error enum which we may be able to remove,
but leave it for now.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/cmd/cbfs.c b/cmd/cbfs.c
index 8e91d4b..10c2c92 100644
--- a/cmd/cbfs.c
+++ b/cmd/cbfs.c
@@ -28,8 +28,7 @@
 			return 1;
 		}
 	}
-	file_cbfs_init(end_of_rom);
-	if (cbfs_get_result() != CBFS_SUCCESS) {
+	if (file_cbfs_init(end_of_rom)) {
 		printf("%s.\n", file_cbfs_error());
 		return 1;
 	}