ACPI, PCI, irq: remove interrupt number restriction

The ACPI compiler uses the extended format when used interrupt numbers
are greater than 15. The extended IRQ syntax is 32 bits according to the
ACPI spec. The code supports parsing the extended interrupt numbers.
However, due to used data structure type; the code silently truncates
interrupt numbers greater than 256.

Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>