Fix typo in documentation (CTR warning)
diff --git a/include/mbedtls/camellia.h b/include/mbedtls/camellia.h
index 1b138fc..74e0961 100644
--- a/include/mbedtls/camellia.h
+++ b/include/mbedtls/camellia.h
@@ -201,7 +201,7 @@
  *             2. Use a randomly-generated \p nonce_counter for each call.
  *             With this strategy, you need to ensure the nonce is generated
  *             in an unbiased way and you must not encrypt more than 2**64
- *             block of data.
+ *             blocks of data.
  *
  *             Note that for both stategies, the limit is in number of blocks
  *             and that a CAMELLIA block is 16 bytes.