x86, irq: Count legacy IRQs by legacy_pic->nr_legacy_irqs instead of NR_IRQS_LEGACY

x86, irq: Count legacy IRQs by legacy_pic->nr_legacy_irqs instead of NR_IRQS_LEGACY

Some platforms, such as Intel MID and mshypv, do not support legacy
interrupt controllers. So count legacy IRQs by legacy_pic->nr_legacy_irqs
instead of hard-coded NR_IRQS_LEGACY.

Signed-off-by: Jiang Liu <[email protected]>
Cc: Tony Luck <[email protected]>
Cc: Joerg Roedel <[email protected]>
Cc: Paul Gortmaker <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: [email protected]
Cc: Benjamin Herrenschmidt <[email protected]>
Cc: Grant Likely <[email protected]>
Cc: Rafael J. Wysocki <[email protected]>
Cc: Bjorn Helgaas <[email protected]>
Cc: Randy Dunlap <[email protected]>
Cc: Yinghai Lu <[email protected]>
Cc: Len Brown <[email protected]>
Cc: Pavel Machek <[email protected]>
Cc: Konrad Rzeszutek Wilk <[email protected]>
Cc: Rob Herring <[email protected]>
Cc: Michal Simek <[email protected]>
Cc: Tony Lindgren <[email protected]>
Acked-by: David Vrabel <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Thomas Gleixner <[email protected]>