scripts: cfe-wfi-tag: fix shebang

Fixes: 72985233a696 ("scripts: support CFE WFI images")
Signed-off-by: Álvaro Fernández Rojas <[email protected]>

scripts/cfe-wfi-tag.py

@@ -1,4 +1,4 @@
-#!/bin/env python3
+#!/usr/bin/env python3
 
 """
 Whole Flash Image Tag