Portduino: Allow limiting TX Power from yaml (#5954)

bin/config-dist.yaml

@@ -78,6 +78,8 @@ Lora:
 #  TXen: x  # TX and RX enable pins
 #  RXen: x
 
+#  SX126X_MAX_POWER: 8  # Limit the output power to 8 dBm, useful for amped nodes
+
 #  spiSpeed: 2000000
 
 ### Set default/fallback gpio chip to use in /dev/. Defaults to 0.
@@ -188,4 +190,4 @@ General:
   MaxMessageQueue: 100
   ConfigDirectory: /etc/meshtasticd/config.d/
 #  MACAddress: AA:BB:CC:DD:EE:FF
-#  MACAddressSource: eth0
+#  MACAddressSource: eth0

bin/config.d/lora-MeshAdv-900M30S.yaml

@@ -7,3 +7,6 @@ Lora:
   TXen: 13
   RXen: 12
   DIO3_TCXO_VOLTAGE: true
+  # Only for E22-900M33S:
+  # Limit the output power to 8 dBm
+  # SX126X_MAX_POWER: 8