USB: cdc-acm: add support for up to 256 devices

Increase the minor range to enable support for up to 256 devices.

Some people are hitting the current 32 device limit. Hopefully 256
minors will be enough for while still.
Signed-off-by: NJohan Hovold <johan@kernel.org>
Acked-by: NOliver Neukum <oneukum@suse.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/class/cdc-acm.h

@@ -19,7 +19,7 @@
  */
 
 #define ACM_TTY_MAJOR		166
-#define ACM_TTY_MINORS		32
+#define ACM_TTY_MINORS		256
 
 /*
  * Requests.