Input: mousedev - move /dev/input/mice to the correct minor

When doing conversion to dynamic input numbers I inadvertently moved
/dev/input/mice from c,13,63 to c,13,31. We need to fix this so that
setups with statically populated /dev continue working.

Tested-by: Krzysztof Mazur <krzysiek@podlesie.net>
Tested-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>