fix pullups not available on fe310

internal/legacy/pinhal_baremetal.go

@@ -9,7 +9,7 @@ func configurePinOut(p PinOutput) {
 }
 
 func configurePinInputPulldown(p PinInput) {
-	configurePin(p, machine.PinInputPulldown)
+	configurePin(p, pulldown) // some chips do not have pull down, in which case pulldown==machine.PinInput.
 }
 
 func configurePinInput(p PinInput) {
@@ -17,7 +17,7 @@ func configurePinInput(p PinInput) {
 }
 
 func configurePinInputPullup(p PinInput) {
-	configurePin(p, machine.PinInputPullup)
+	configurePin(p, pullup) // some chips do not have pull up, in which case pullup==machine.PinInput.
 }
 
 func pinIsNoPin(a any) bool {

internal/legacy/pinhal_nopulls.go

@@ -0,0 +1,10 @@
+//go:build baremetal && fe310
+
+package legacy
+
+import "machine"
+
+const (
+	pulldown = machine.PinInput
+	pullup   = machine.PinInput
+)

internal/legacy/pinhal_pulls.go

@@ -0,0 +1,10 @@
+//go:build baremetal && !fe310
+
+package legacy
+
+import "machine"
+
+const (
+	pulldown = machine.PinInputPulldown
+	pullup   = machine.PinInputPullup
+)