usb-storage: make shuttle_usbat a separate module

This patch (as1211) converts usb-storage's shuttle_usbat subdriver
into a separate module.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/usb/storage/Kconfig b/drivers/usb/storage/Kconfig
index 2c73fa9..44c6b19 100644
--- a/drivers/usb/storage/Kconfig
+++ b/drivers/usb/storage/Kconfig
@@ -64,7 +64,7 @@
 	  If this driver is compiled as a module, it will be named ums-isd200.
 
 config USB_STORAGE_USBAT
-	bool "USBAT/USBAT02-based storage support"
+	tristate "USBAT/USBAT02-based storage support"
 	depends on USB_STORAGE
 	help
 	  Say Y here to include additional code to support storage devices
@@ -84,6 +84,8 @@
 	  - RCA LYRA MP3 portable
 	  - Sandisk ImageMate SDDR-05b
 
+	  If this driver is compiled as a module, it will be named ums-usbat.
+
 config USB_STORAGE_SDDR09
 	tristate "SanDisk SDDR-09 (and other SmartMedia, including DPCM) support"
 	depends on USB_STORAGE