firewire: add minor number range check to fw_device_init()

fw_device_init() didn't check whether the allocated minor number isn't
too large.  Fail if it goes overflows MINORBITS.

Signed-off-by: Tejun Heo <tj@kernel.org>
Suggested-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Acked-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>