Staging: wlan-ng: Update Help text to mention prism3 devices.

The driver also supports prism3 devices
Signed-off-by: NSolomon Peachy <pizza@shaftnet.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

drivers/staging/wlan-ng/Kconfig

 config PRISM2_USB
-	tristate "Prism2.5 USB driver"
+	tristate "Prism2.5/3 USB driver"
 	depends on WLAN_80211 && USB
 	default n
 	---help---
-	  This is the wlan-ng prism 2.5 USB driver for a wide range of
+	  This is the wlan-ng prism 2.5/3 USB driver for a wide range of
 	  old USB wireless devices.
 
 	  To compile this driver as a module, choose M here: the module