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: 0ad64007feb9 ("efi_loader: set load options in boot manager")
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
diff --git a/lib/efi_loader/efi_bootmgr.c b/lib/efi_loader/efi_bootmgr.c
index 61dc72a..d3be2f9 100644
--- a/lib/efi_loader/efi_bootmgr.c
+++ b/lib/efi_loader/efi_bootmgr.c
@@ -275,7 +275,7 @@
 		memcpy(*load_options, lo.optional_data, size);
 		ret = efi_set_load_options(*handle, size, *load_options);
 	} else {
-		load_options = NULL;
+		*load_options = NULL;
 	}
 
 error: