pioasm_neopixel: Fix pin specifications, drop unneeded init=

Author: jepler

examples/pioasm_neopixel.py

@@ -28,9 +28,8 @@
 sm = rp2pio.StateMachine(
     assembled,
     frequency=800000 * 6,  # 800khz * 6 clocks per bit
-    init=adafruit_pioasm.assemble("set pindirs 1"),
-    first_set_pin=board.D12,
-    first_sideset_pin=board.D12,
+    first_set_pin=board.GP12,
+    first_sideset_pin=board.GP12,
     auto_pull=True,
     out_shift_right=False,
     pull_threshold=8,