This is a backport form the SMP branch. Not required here, it only makes life
for SMP easier. And future merging too.
- filling the IDT is removed from prot_init()
- struct gate_table_s is a public type
- gate_table_pic is a global array as it is used by APIC code too
- idt_copy_vectors() is also global and used by idt_init() as well as
apic_idt_init()
- idt_init() is called right after prot_init() in system_init()
4903a734b8