must be set *after* initializing the lapic[TIMER] vector.

Doing this, we now get clock interrupts on cpu 1.
(No idea why we always got them on cpu 0.)

Don't write to TCCR - it is read-only.

panic if unknown fault with CPL=0 (i.e. in kernel)

to take inode* instead of minor number.

Unlock console inode during console_read
and console_write.  Otherwise background
processes cannot write to console while the
shell is reading it waiting for input.