regmap IRQ support for devices with multiple IRQs

regmap IRQ support for devices with multiple IRQs

Merge series from Matti Vaittinen <mazziesaccount@gmail.com>:

Devices can provide multiple interrupt lines. One reason for this is that
a device has multiple subfunctions, each providing its own interrupt line.
Another reason is that a device can be designed to be used (also) on a
system where some of the interrupts can be routed to another processor.

A line often further acts as a demultiplex for specific interrupts
and has it's respective set of interrupt (status, mask, ack, ...)
registers.

Regmap supports the handling of these registers and demultiplexing
interrupts, but interrupt domain code ends up assigning the same name for
the per interrupt line domains

This series adds possibility for giving a name suffix for an interrupt

Previous discussion can be found from:
https://lore.kernel.org/all/87plst28yk.ffs@tglx/
https://lore.kernel.org/all/15685ef6-92a5-41df-9148-1a67ceaec47b@gmail.com/

The domain suffix support added in this series will be used by the
ROHM BD96801 ERRB IRQ support code. The BD96801 ERRB support will need
the initial BD96801 driver code, which is not yet in irq/core or regmap
trees. Thus the user for this new support is not included in the series,
but will be sent once the name suffix support gets merged.