cros_setup_toolchains: update lddtree ParseELF call

Change to using keyword args to avoid future breakage.

BUG=chromium:398098
BUG=chromium:393018
TEST=`cros_setup_toolchains --create-packages -t arm-none-eabi` works again

Change-Id: I289ce877b7b221e6ba9b8b11825cfab8c4887015
Reviewed-on: https://chromium-review.googlesource.com/210358
Reviewed-by: Mike Frysinger <vapier@chromium.org>
Tested-by: Mike Frysinger <vapier@chromium.org>
diff --git a/scripts/cros_setup_toolchains.py b/scripts/cros_setup_toolchains.py
index 6d6707a..37809e3 100644
--- a/scripts/cros_setup_toolchains.py
+++ b/scripts/cros_setup_toolchains.py
@@ -755,7 +755,7 @@
   osutils.SafeMakedirs(libdir)
   donelibs = set()
   for elf in elfs:
-    e = lddtree.ParseELF(elf, root, ldpaths)
+    e = lddtree.ParseELF(elf, root=root, ldpaths=ldpaths)
     interp = e['interp']
     if interp:
       # Generate a wrapper if it is executable.