gen_hashed_bin: use integer division operator

Use // instead of /, so this script will be compatible
with both python2 and python3.

Signed-off-by: Volodymyr Babchuk <vlad.babchuk@gmail.com>
Acked-by: Jens Wiklander <jens.wiklander@linaro.org>
Reviewed-by: Joakim Bech <joakim.bech@linaro.org>
diff --git a/scripts/gen_hashed_bin.py b/scripts/gen_hashed_bin.py
index cf5175a..25a9596 100755
--- a/scripts/gen_hashed_bin.py
+++ b/scripts/gen_hashed_bin.py
@@ -145,7 +145,7 @@
     tee_pageable_fname = args.tee_pageable_bin
     pager_input_size = os.path.getsize(tee_pager_fname)
     paged_input_size = os.path.getsize(tee_pageable_fname)
-    hash_size = paged_input_size / (4 * 1024) * \
+    hash_size = paged_input_size // (4 * 1024) * \
         hashlib.sha256().digest_size
 
     if paged_input_size % (4 * 1024) != 0: