misc: small fix or general refactoring i did not bother commenting

pwnagotchi/mesh/wifi.py

@@ -1 +1,12 @@
 NumChannels = 140
+
+
+def freq_to_channel(freq):
+    if freq <= 2472:
+        return int(((freq - 2412) / 5) + 1)
+    elif freq == 2484:
+        return int(14)
+    elif 5035 <= freq <= 5865:
+        return int(((freq - 5035) / 5) + 7)
+    else:
+        return 0