n64: cosmetics changes

Make the variable declaration ascending order and initialize the
variables at the time of declaration when possible.

Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: Lauri Kasanen <cand@gmx.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>