libs/hardware/ir: Code optimization.

Signed-off-by: lbuque <1102390310@qq.com>

Author: lbuque

m5stack/libs/hardware/ir.py

@@ -2,22 +2,21 @@
 import M5
 from machine import Pin
 
-_pin_map = {
-    M5.BOARD.M5AtomS3: (None, 4),
-    M5.BOARD.M5AtomS3Lite: (None, 4),
-    M5.BOARD.M5AtomS3U: (None, 12),
-    M5.BOARD.M5Capsule: (None, 4),
-    M5.BOARD.M5Cardputer: (None, 44),
-    M5.BOARD.M5StickCPlus: (None, 9),
-    M5.BOARD.M5StickC: (None, 9),
-    M5.BOARD.M5StickCPlus2: (None, 19),
-    M5.BOARD.M5AtomU: (None, 12),
-}
-
-
 class IR:
+    _pin_map = {
+        M5.BOARD.M5AtomS3: (None, 4),
+        M5.BOARD.M5AtomS3Lite: (None, 4),
+        M5.BOARD.M5AtomS3U: (None, 12),
+        M5.BOARD.M5Capsule: (None, 4),
+        M5.BOARD.M5Cardputer: (None, 44),
+        M5.BOARD.M5StickCPlus: (None, 9),
+        M5.BOARD.M5StickC: (None, 9),
+        M5.BOARD.M5StickCPlus2: (None, 19),
+        M5.BOARD.M5AtomU: (None, 12),
+    }
+
     def __init__(self) -> None:
-        self._port = _pin_map.get(M5.getBoard())
+        self._port = self._pin_map.get(M5.getBoard())
         self._transmitter = NEC(Pin(self._port[1], Pin.OUT, value=0))
         self._receiver = None