x86: Prepare the affinity common functions for taking struct irq_data *

While at it rename it to sensible function names and fix the return
value from unsigned to int for __ioapic_set_affinity (set_desc_affinity).
Returning -1 in a function returning unsigned int is somewhat strange.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ingo Molnar <mingo@elte.hu>