xtensa: add IRQ domains support

IRQ domains provide a mechanism for conversion of linux IRQ numbers to
hardware IRQ numbers and vice versus. It is used by OpenFirmware for
linking device tree objects to their respective interrupt controllers.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Chris Zankel <chris@zankel.net>
3 files changed