remove devkbin and devkbmap. use devpckb instead

Reference: /n/atom/patch/applied/nokbin
Date: Thu May 15 02:45:17 CES 2014
Signed-off-by: quanstro@quanstro.net

# rm /sys/src/nix/port/devkbin.c
# rm /sys/src/nix/port/devkbmap.c