x86, apic: Fix false positive section mismatch in numaq_32.c
The variable apic_numaq placed in noninit section references the
function wakeup_secondary_cpu_via_nmi(), which is in __cpuinit
section. Thus causes a section mismatch warning. To avoid such
mismatch we mark apic_numaq as __refdata.
We were warned by the following warning:
WARNING: arch/x86/kernel/built-in.o(.data+0x932c): Section mismatch in
reference from the variable apic_numaq to the function
.cpuinit.text:wakeup_secondary_cpu_via_nmi()