bootm: Reduce arguments to boot_get_loadables()

This function only uses two arguments. The 'arch' always has a constant
value, so drop it. This simplifies the function call.

Tidy up the function comment while we are here.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@konsulko.com>
diff --git a/boot/bootm.c b/boot/bootm.c
index ae3fceb..aae097d 100644
--- a/boot/bootm.c
+++ b/boot/bootm.c
@@ -563,8 +563,7 @@
 	}
 
 	/* find all of the loadables */
-	ret = boot_get_loadable(argc, argv, &images, IH_ARCH_DEFAULT,
-			       NULL, NULL);
+	ret = boot_get_loadable(&images);
 	if (ret) {
 		printf("Loadable(s) is corrupt or invalid\n");
 		return 1;