[HAL][GENRIC] Update of HAL_GetTickFreq() brief

Src/stm32f7xx_hal.c

diff --git a/Src/stm32f7xx_hal.c b/Src/stm32f7xx_hal.c
index c27bce0..222bb51 100644
--- a/Src/stm32f7xx_hal.c
+++ b/Src/stm32f7xx_hal.c
@@ -346,7 +346,8 @@
 
 /**
   * @brief Return tick frequency.
-  * @retval tick period in Hz
+  * @retval Tick frequency.
+  *         Value of @ref HAL_TickFreqTypeDef.
   */
 HAL_TickFreqTypeDef HAL_GetTickFreq(void)
 {