Handle parallel builds

Change-Id: I142057dfe9429b6360fafcae4f9e1b4b8140f3d5
diff --git a/scripts/generate_binaries.py b/scripts/generate_binaries.py
index f206cf8..8eccc14 100755
--- a/scripts/generate_binaries.py
+++ b/scripts/generate_binaries.py
@@ -31,8 +31,7 @@
         elf = elffile.ELFFile(f)
         for segment in elf.iter_segments():
             if segment['p_type'] == 'PT_LOAD' and segment['p_filesz'] > 0:
-                if not os.path.exists(args.output):
-                    os.makedirs(args.output)
+                os.makedirs(args.output, exist_ok=True)
                 out = os.path.join(
                         args.output,
                         '%s_0x%08x.bin' % (os.path.basename(args.input), segment['p_paddr']))