Arduino.h: fix DIGITAL_PIN_EXISTS macro to avoid comment expansion issues

The DIGITAL_PIN_EXISTS macro (used e.g. by LED_BUILTIN) was not working
properly because the inline comments in devicetree_generated.h were
confusing the preprocessor: one internal macro tried to create an
unsigned constant by pasting a '*/' comment end marker with the 'U'
character.

Splitting that macro into two parts, so that the DT_REG_ADDR macro is
invoked with an expanded argument, fixes the issue.

-------------------------------------------------------------------

Pick: arduino@84651c2c

Signed-off-by: Luca Burelli <l.burelli@arduino.cc>
Signed-off-by: TOKITA Hiroshi <tokita.hiroshi@gmail.com>

Author: pillo79

cores/arduino/Arduino.h

@@ -15,10 +15,11 @@
 #include <zephyr/drivers/i2c.h>
 
 #if DT_PROP_LEN(DT_PATH(zephyr_user), digital_pin_gpios) > 0
+/* Note: DT_REG_ADDR needs an expanded argument or it will not work properly */
+#define DIGITAL_PIN_MATCHES(dev_pha, pin, dev, num)                                                \
+	(((dev == DT_REG_ADDR(dev_pha)) && (num == pin)) ? 1 : 0)
 #define DIGITAL_PIN_EXISTS(n, p, i, dev, num)                                                      \
-	(((dev == DT_REG_ADDR(DT_PHANDLE_BY_IDX(n, p, i))) && (num == DT_PHA_BY_IDX(n, p, i, pin))) ?  \
-		 1 :                                                                                       \
-		 0)
+	DIGITAL_PIN_MATCHES(DT_PHANDLE_BY_IDX(n, p, i), DT_PHA_BY_IDX(n, p, i, pin), dev, num)
 
 /* Check all pins are defined only once */
 #define DIGITAL_PIN_CHECK_UNIQUE(i, _)                                                             \