wwan: fix hotplug event handling

Hotplug manager send: "remove" -> "add" -> "bind" events,
script interpret bind as "not add" = "remove" and mark device
as unavailable.

Signed-off-by: Rozhuk Ivan <rozhuk.im@gmail.com>
Signed-off-by: Hans Dedecker <dedeckeh@gmail.com> [PKG_RELEASE increase]