examples/hwapi: Consistently use Signal class to define LEDs.

examples/hwapi/hwconfig_dragonboard410c.py

@@ -13,10 +13,10 @@ from machine import Pin
 # echo -n "gpio_keys" >/sys/class/input/input1/device/driver/unbind
 
 # User LED 1 on gpio21
-LED = Pin(21, Pin.OUT)
+LED = Signal(Pin(21, Pin.OUT))
 
 # User LED 2 on gpio120
-LED2 = Pin(120, Pin.OUT)
+LED2 = Signal(Pin(120, Pin.OUT))
 
 # Button S3 on gpio107
 BUTTON = Pin(107, Pin.IN)

examples/hwapi/hwconfig_z_frdm_k64f.py

@@ -2,4 +2,4 @@ from machine import Pin
 
 # Freescale/NXP FRDM-K64F board
 # Blue LED on port B, pin 21
-LED = Pin(("GPIO_1", 21), Pin.OUT)
+LED = Signal(Pin(("GPIO_1", 21), Pin.OUT))