De-assert PIC IRQs properly at APIC level

De-assert PIC IRQs properly at APIC level

[ Taking latest isapc changes into account. ]

Ensure that PIC-delivered IRQs are properly de-asserted in case the APIC
is in EXTINT or FIXED mode (with level-triggering selected) on LINT0.
Fixes EFI-BIOS boot issues.

This patch also cleans up a bit the interface between PIC and APIC,
making apic_local_deliver private again.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5041 c046a42c-6fe2-441c-8c8c-71466251a162