uio: use threaded interrupts

Split the existing uio_interrupt into a hardirq handler and a thread
function. The hardirq handler deals with the interrupt source in
hardware, the thread function notifies userspace that there is an event
to be handled.

Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
Link: https://lore.kernel.org/r/20240408234050.2056374-3-chris.packham@alliedtelesis.co.nz


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>