try to fix the Doxygen and style problem

Author: wdx04

hal/include/hal/can_api.h

@@ -90,28 +90,36 @@ void can_init_direct(can_t *obj, const can_pinmap_t *pinmap);
  * @param obj CAN object
  * @param rd The CAN RD pin name
  * @param td The CAN TD pin name
+#ifdef DEVICE_CAN_FD
  * @param hz The bus frequency in classical CAN mode, or nominal phase frequency in CAN FD mode
  * @param data_hz The data phase frequency in CAN FD mode, the CAN object is put into Classical CAN mode if this parameter is zero
+#else
+ * @param hz The bus frequency
+#endif
  */
 void can_init_freq(can_t *obj, PinName rd, PinName td, int hz
 #ifdef DEVICE_CAN_FD
-    , int data_hz
+                   , int data_hz
 #endif
-    );
+                  );
 
 /** Initialize the CAN peripheral. It sets the default parameters for CAN
  *  peripheral, and configures its specifieds pins.
  *
  * @param obj CAN object
  * @param pinmap pointer to structure which holds static pinmap
+#ifdef DEVICE_CAN_FD
  * @param hz The bus frequency in classical CAN mode, or nominal phase frequency in CAN FD mode
  * @param data_hz The data phase frequency in CAN FD mode, the CAN object is put into Classical CAN mode if this parameter is zero
+#else
+ * @param hz The bus frequency
+#endif
  */
 void can_init_freq_direct(can_t *obj, const can_pinmap_t *pinmap, int hz
 #ifdef DEVICE_CAN_FD
-    , int data_hz
+                          , int data_hz
 #endif
-    );
+                         );
 
 /** Release the CAN peripheral, not currently invoked. It requires further
  *  resource management.
@@ -123,14 +131,18 @@ void can_free(can_t *obj);
 /** Configure the CAN bus frequency
  *
  * @param obj The CAN object
+#ifdef DEVICE_CAN_FD
  * @param hz The bus frequency in classical CAN mode, or nominal phase frequency in CAN FD mode
  * @param data_hz The data phase frequency in CAN FD mode, the CAN object is put into Classical CAN mode if this parameter is zero
+#else
+ * @param hz The bus frequency
+#endif
  */
 int can_frequency(can_t *obj, int hz
 #ifdef DEVICE_CAN_FD
-    , int data_hz
+                  , int data_hz
 #endif
-    );
+                 );
 
 /** Initialize the CAN IRQ handler
  *