x86: use 28 bits irq NR for pci msi/msix and ht

also print out irq no in /proc/interrups and /proc/stat in hex, so could
tell bus/dev/func.

Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>