genirq: Don't allow user space to set IRQ affinity to isolated CPUs

The PM_QOS_CPU_DMA_LATENCY QOS request attached to an IRQ is ignored
if the IRQ is affined to an isolated CPU. As isolated CPUs enter
deep sleep state, it is better not to affine IRQs to those CPUs.

Change-Id: I0cf178bc6f87c9dd5e863a58b6bb917a8e183bd9
Signed-off-by: Pavankumar Kondeti <pkondeti@codeaurora.org>
Signed-off-by: Satya Durga Srinivasu Prabhala <satyap@codeaurora.org>