ACPI: Using correct irq when waiting for events

When the system is waiting for GPE/fixed event handler to finish,
it uses acpi_gbl_FADT.sci_interrupt directly as the IRQ number.
However, the remapped IRQ returned by acpi_gsi_to_irq() should be
passed to synchronize_hardirq() instead of it.

Cc: 3.19+ <stable@vger.kernel.org> # 3.19+
Acked-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Chen Yu <yu.c.chen@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>