The AIDET (ARM Interrupt Detector Add-on Circuit) is a kind of
syscon block related with the interrupt controller.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Since no clock driver is implemented for peripherals in U-Boot yet,
this property is needed for the serial driver to set up the divisor
register.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>