HKDF: Fix style issue
diff --git a/include/mbedtls/hkdf.h b/include/mbedtls/hkdf.h
index 6833e72..235c5ad 100644
--- a/include/mbedtls/hkdf.h
+++ b/include/mbedtls/hkdf.h
@@ -99,8 +99,8 @@
*
* \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.