Fix non-critical interrupts (e.g. keyboard)

[nougatchi]

Possible sources of the problem

kernel

• kentry.asm

libc

• isr.c
• interrupt.h
• interrupt.c

drivers

• pic.c
• keyboard.c

IRQ0 (timer) never gets hit, nor does IRQ1 (keyboard) get hit.

Graph of where the errors could be

              +---+ improper driver?? +-----+
         +---->PIC<-------------------+pic.c|
         |    +-+-+                   +-----+
         |      |
         |      |
         |      |
         |      |
         |    +-v-+  improper idt???  +-----------+
         |    |IDT<-------------------+interrupt.c|
         |    +-+-+                   +-----------+
         |      |
         |      |
         |      |
         |      |
         |    +-v-+  improper isr???? +-----+
         +----+ISR<-------------------+isr.c|
not sending   +-+-+                   +-----+
   pic eoi??    |
                |
                |
              +-v+ bad ps/2 init????? +----------+
              |KB<--------------------+keyboard.c|
              +--+                    +----------+

[nougatchi]

Seems to be under control, rewriting some of the interrupts.