HSI: cmt_speech: unmark comments as kernel-doc

Fix build warnings from the kernel test robot:

drivers/hsi/clients/cmt_speech.c:831: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst
    * Block until pending data transfers have completed.
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reported-by: kernel test robot <lkp@intel.com>
Cc: Aditya Srivastava <yashsri421@gmail.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>

drivers/hsi/clients/cmt_speech.c

@@ -827,7 +827,7 @@ static int check_buf_params(struct cs_hsi_iface *hi,
 	return r;
 }
 
-/**
+/*
  * Block until pending data transfers have completed.
  */
 static int cs_hsi_data_sync(struct cs_hsi_iface *hi)
@@ -850,7 +850,7 @@ static int cs_hsi_data_sync(struct cs_hsi_iface *hi)
 			r = -ERESTARTSYS;
 			goto out;
 		}
-		/**
+		/*
 		 * prepare_to_wait must be called with hi->lock held
 		 * so that callbacks can check for waitqueue_active()
 		 */