stm32/boards/NUCLEO_F767ZI: Fix up comments about HCLK computation.

ports/stm32/boards/NUCLEO_F767ZI/mpconfigboard.h

@@ -16,20 +16,12 @@
 #define MICROPY_BOARD_EARLY_INIT    NUCLEO_F767ZI_board_early_init
 void NUCLEO_F767ZI_board_early_init(void);
 
-// HSE is 25MHz
-// VCOClock = HSE * PLLN / PLLM = 25 MHz * 432 / 25 = 432 MHz
-// SYSCLK = VCOClock / PLLP = 432 MHz / 2 = 216 MHz
-// USB/SDMMC/RNG Clock = VCOClock / PLLQ = 432 MHz / 9 = 48 MHz
+// HSE is 8MHz
 #define MICROPY_HW_CLK_PLLM (4)
 #define MICROPY_HW_CLK_PLLN (216)
 #define MICROPY_HW_CLK_PLLP (RCC_PLLP_DIV2)
 #define MICROPY_HW_CLK_PLLQ (9)
-
-// From the reference manual, for 2.7V to 3.6V
-// 151-180 MHz => 5 wait states
-// 181-210 MHz => 6 wait states
-// 211-216 MHz => 7 wait states
-#define MICROPY_HW_FLASH_LATENCY    FLASH_LATENCY_7 // 210-216 MHz needs 7 wait states
+#define MICROPY_HW_FLASH_LATENCY (FLASH_LATENCY_7) // 210-216 MHz needs 7 wait states
 
 // UART config
 #define MICROPY_HW_UART2_TX         (pin_D5)