By default the kernel sets a value for default affinity which may
not correspond to the real bitmap of potentially online CPUs. E.g.
for ARC HS processors with 2 cores the default value of affinity in
the kernel may be 0xF and it is wrong in this case. This happens
because init_irq_default_affinity
Ignore value of interrupt distribution mode for common interrupts in
IDU since setting of affinity using value from Device Tree is deprecated
in ARC. Originally it is done in idu_irq_xlate() function and it is
semantically wrong and does not guaranty that an affinity value will be
set properly. idu
