M263: Exclude USB UART from testing

USB UART is dedicated to USB COM and so must exclude from FPGA CI testing.

targets/TARGET_NUVOTON/TARGET_M261/pinmap.c

@@ -18,6 +18,7 @@
 #include "mbed_assert.h"
 #include "pinmap.h"
 #include "PortNames.h"
+#include "PeripheralNames.h"
 #include "mbed_error.h"
 
 /**
@@ -83,3 +84,17 @@ void pin_mode(PinName pin, PinMode mode)
      */
 }
 
+/* List of peripherals excluded from testing */
+const PeripheralList *pinmap_restricted_peripherals()
+{
+    static const int perifs[] = {
+        STDIO_UART          // Dedicated to USB VCOM
+    };
+
+    static const PeripheralList peripheral_list = {
+        sizeof(perifs) / sizeof(perifs[0]),
+        perifs
+    };
+
+    return &peripheral_list;
+}