udev: Always enumerate wifi phys from 0

At least RPI4 this enumaration feels pretty random.

board/common/rootfs/etc/udev/rules.d/60-rename-wifi-phy.rules

@@ -1,3 +1,3 @@
 # Rename WiFi PHY devices from phy0 to radio0 to avoid name clashes
 SUBSYSTEM=="ieee80211", ACTION=="add", KERNEL=="phy*", \
-  RUN+="/bin/sh -c '/usr/sbin/iw phy %k set name radio%n'"
+  RUN+="/usr/libexec/infix/rename-wifi-phy %k"

board/common/rootfs/usr/libexec/infix/rename-wifi-phy

@@ -0,0 +1,8 @@
+#!/bin/sh
+# Rename WiFi PHY to radio{N}, enumerating from 0
+phy="$1"
+n=0
+while [ -d "/sys/class/ieee80211/radio$n" ]; do
+    n=$((n + 1))
+done
+/usr/sbin/iw phy "$phy" set name "radio$n"