binman: Convert to using the ifwitool bintool

Update the ifwi entry type to use this bintool, instead of running
ifwitool directly. This simplifies the code and provides more
consistency as well as supporting missing bintools.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/tools/binman/ftest.py b/tools/binman/ftest.py
index 92bcb74..f543d17 100644
--- a/tools/binman/ftest.py
+++ b/tools/binman/ftest.py
@@ -2314,8 +2314,8 @@
         # We expect to find the TPL wil in subpart IBBP entry IBBL
         image_fname = tools.GetOutputFilename('image.bin')
         tpl_fname = tools.GetOutputFilename('tpl.out')
-        tools.RunIfwiTool(image_fname, tools.CMD_EXTRACT, fname=tpl_fname,
-                          subpart='IBBP', entry_name='IBBL')
+        ifwitool = bintool.Bintool.create('ifwitool')
+        ifwitool.extract(image_fname, 'IBBP', 'IBBL', tpl_fname)
 
         tpl_data = tools.ReadFile(tpl_fname)
         self.assertEqual(U_BOOT_TPL_DATA, tpl_data[:len(U_BOOT_TPL_DATA)])