HKDF: Fix style issue
@@ -99,8 +99,8 @@ int mbedtls_hkdf_extract( const mbedtls_md_info_t *md,
*
* \param md A hash function; md.size denotes the length of the hash
* function output in bytes.
- * \param prk A pseudorandom key of at least md.size bytes. \p prk is usually,
- * the output from the HKDF extract step.
+ * \param prk A pseudorandom key of at least md.size bytes. \p prk is
+ * usually the output from the HKDF extract step.
* \param prk_len The length in bytes of \p prk.
* \param info An optional context and application specific information
* string. This can be a zero-length string.
