Less magic number

Less magic number

For PS/2 - status byte - bit 5:
The bit is '1' if the data on input port 60h came from the AUX port, or '0' if
the data came from the keyboard or from the keyboard controller itself.

KBS_TERR (kbd transmission error) was valid for AT-mode, but not for PS/2-mode.

ok ratchov@, miod@