Fix empty HAS_TIMER macros

Marlin/src/HAL/HAL_STM32/fastio_STM32.h

@@ -80,7 +80,7 @@ void FastIO_init(); // Must be called before using fast io macros
 
 #define IS_INPUT(IO)
 #define IS_OUTPUT(IO)
-#define HAS_TIMER(IO)
+#define HAS_TIMER(IO)           digitalPinHasPWM(IO)
 
 #define PWM_PIN(P)              HAS_TIMER(P)
 #define USEABLE_HARDWARE_PWM(P) PWM_PIN(P)

Marlin/src/HAL/HAL_STM32F4/fastio_STM32F4.h

@@ -50,9 +50,9 @@
 
 #define IS_INPUT(IO)
 #define IS_OUTPUT(IO)
-#define HAS_TIMER(IO)
+#define HAS_TIMER(IO)           true
 
-#define PWM_PIN(P)              true
+#define PWM_PIN(P)              HAS_TIMER(P)
 #define USEABLE_HARDWARE_PWM(P) PWM_PIN(P)
 
 // digitalRead/Write wrappers

Marlin/src/HAL/HAL_STM32F7/fastio_STM32F7.h

@@ -49,9 +49,9 @@
 
 #define IS_INPUT(IO)
 #define IS_OUTPUT(IO)
-#define HAS_TIMER(IO)
+#define HAS_TIMER(IO)           true
 
-#define PWM_PIN(P)              true
+#define PWM_PIN(P)              HAS_TIMER(P)
 #define USEABLE_HARDWARE_PWM(P) PWM_PIN(P)
 
 // digitalRead/Write wrappers