wifi: wilc1000: do not realloc workqueue everytime an interface is added

In the Linux kernel, the following vulnerability has been resolved:

wifi: wilc1000: do not realloc workqueue everytime an interface is added

Commit 09ed8bfc5215 ("wilc1000: Rename workqueue from "WILC_wq" to
"NETDEV-wq"") moved workqueue creation in wilc_netdev_ifc_init in order to
set the interface name in the workqueue name. However, while the driver
needs only one workqueue, the wilc_netdev_ifc_init is called each time we
add an interface over a phy, which in turns overwrite the workqueue with a
new one. This can be observed with the following commands:

for i in $(seq 0 10)
do
iw phy phy0 interface add wlan1 type managed
iw dev wlan1 del
done
ps -eo pid,comm|grep wlan

39 kworker/R-wlan0
98 kworker/R-wlan1
102 kworker/R-wlan1
105 kworker/R-wlan1
108 kworker/R-wlan1
111 kworker/R-wlan1
114 kworker/R-wlan1
117 kworker/R-wlan1
120 kworker/R-wlan1
123 kworker/R-wlan1
126 kworker/R-wlan1
129 kworker/R-wlan1

Fix this leakage by putting back hif_workqueue allocation in
wilc_cfg80211_init. Regarding the workqueue name, it is indeed relevant to
set it lowercase, however it is not attached to a specific netdev, so
enforcing netdev name in the name is not so relevant. Still, enrich the
name with the wiphy name to make it clear which phy is using the workqueue.