efi_loader: avoid invalid free

load_options passed from do_efibootmgr() to do_bootefi_exec() may contain
invalid data from the stack which will lead to an invalid free().

Fixes: 0ad64007

 ("efi_loader: set load options in boot manager")
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>

lib/efi_loader/efi_bootmgr.c

@@ -275,7 +275,7 @@ static efi_status_t try_load_entry(u16 n, efi_handle_t *handle,
 		memcpy(*load_options, lo.optional_data, size);
 		ret = efi_set_load_options(*handle, size, *load_options);
 	} else {
-		load_options = NULL;
+		*load_options = NULL;
 	}
 
 error: