dm: x86: quark: Add an interrupt driver

Add a driver for interrupts on quark and move the code currently in
cpu_irq_init() into its probe() method.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Tested-by: Bin Meng <bmeng.cn@gmail.com>