feature: make RNG implementation shared for rp2040/rp2350

Signed-off-by: deadprogram <[email protected]>

src/machine/machine_rp2040_rng.go → src/machine/machine_rp2_rng.go

@@ -1,4 +1,4 @@
-//go:build rp2040
+//go:build rp2040 || rp2350
 
 // Implementation based on code located here:
 // https://github.com/raspberrypi/pico-sdk/blob/master/src/rp2_common/pico_lwip/random.c