Fix a few typos
diff --git a/include/mbedtls/chacha20.h b/include/mbedtls/chacha20.h
index d7a0750..47bd7d3 100644
--- a/include/mbedtls/chacha20.h
+++ b/include/mbedtls/chacha20.h
@@ -139,7 +139,7 @@
  *                  \c mbedtls_chacha20_starts() must be called at least once
  *                  to setup the context before this function can be called.
  *
- * \note            This function can be called mutliple times in a row in
+ * \note            This function can be called multiple times in a row in
  *                  order to encrypt of decrypt data piecewise with the same
  *                  key and nonce.
  *