telephony: phonedev panics if unregistering device not registered [Bug 9266]

Remove panic from phonedev.  See

	http://bugzilla.kernel.org/show_bug.cgi?id=9266

for details (phonedev panics if unregistering device not registered).
Signed-off-by: NMatti Linnanvuori <mattilinnanvuori@yahoo.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

drivers/telephony/phonedev.c

@@ -120,9 +120,8 @@ int phone_register_device(struct phone_device *p, int unit)
 void phone_unregister_device(struct phone_device *pfd)
 {
 	mutex_lock(&phone_lock);
-	if (phone_device[pfd->minor] != pfd)
-		panic("phone: bad unregister");
-	phone_device[pfd->minor] = NULL;
+	if (likely(phone_device[pfd->minor] == pfd))
+		phone_device[pfd->minor] = NULL;
 	mutex_unlock(&phone_lock);
 }