The IDU intc is technically part of MCIP (Multi-core IP) hence historically was only available in a SMP hardware build (and thus only in a SMP kernel build). Now that hardware restriction has been lifted, so a UP kernel needs to support it. This requires breaking mcip.c into parts which are strictly SMP (inter-core interrupts) and IDU which in reality is just another intc and thus has no bearing on SMP. This change allows IDU in UP builds and with a suitable device tree, we can have the cascaded intc system ARCv2 core intc <---> ARCv2 IDU intc <---> periperals Signed-off-by: Vineet Gupta <vgupta@synopsys.com>