scripts/mkknlimg: Change string for DDT detection

The old "of_overlay_apply" string does not appear in 4.8 kernel builds.
"of_cfs_init" is both present and a more accurate indication of support
for dynamically loading overlays (although the trailer is now of little
practical use and the firmware assumes DT support and will look for
both .dtbo and -overlay.dtb overlays).

Signed-off-by: Phil Elwell <[email protected]>

Author: Phil Elwell

scripts/mkknlimg

@@ -77,7 +77,7 @@ my $wanted_strings =
 	'brcm,bcm2709' => FLAG_PI | FLAG_DTOK | FLAG_270X,
 	'brcm,bcm2835' => FLAG_PI | FLAG_DTOK | FLAG_283X,
 	'brcm,bcm2836' => FLAG_PI | FLAG_DTOK | FLAG_283X,
-	'of_overlay_apply' => FLAG_DTOK | FLAG_DDTK,
+	'of_cfs_init' => FLAG_DTOK | FLAG_DDTK,
 };
 
 my $res = try_extract($kernel_file, $tmpfile1);