x86: make 32bit support per_cpu vector

so we can merge io_apic_32.c and io_apic_64.c

v2: Use cpu_online_map as target cpus for bigsmp, just like 64-bit is doing.

Also remove some unused TARGET_CPUS macro.

v3: need to check if desc is null in smp_irq_move_cleanup

also migration needs to reset vector too, so copy __target_IO_APIC_irq
from 64bit.

(the duplication will go away once the two files are unified.)

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

arch/x86/kernel/entry_32.S

@@ -629,7 +629,7 @@ ENTRY(interrupt)
 ENTRY(irq_entries_start)
 	RING0_INT_FRAME
 vector=0
-.rept NR_IRQS
+.rept NR_VECTORS
 	ALIGN
  .if vector
 	CFI_ADJUST_CFA_OFFSET -4