USB: cdc-acm.c: Fix compile warnings

The irq flags should be unsigned long.

  CC [M]  drivers/usb/class/cdc-acm.o
drivers/usb/class/cdc-acm.c: In function 'acm_waker':
drivers/usb/class/cdc-acm.c:527: warning: comparison of distinct pointer types lacks a cast
drivers/usb/class/cdc-acm.c:529: warning: comparison of distinct pointer types lacks a cast

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/class/cdc-acm.c

@@ -512,7 +512,7 @@ static void acm_softint(struct work_struct *work)
 static void acm_waker(struct work_struct *waker)
 {
 	struct acm *acm = container_of(waker, struct acm, waker);
-	long flags;
+	unsigned long flags;
 	int rv;
 
 	rv = usb_autopm_get_interface(acm->control);