irqchip/sunxi-nmi: Support Allwinner A523 NMI controller

The NMI controller in the Allwinner A523 is almost compatible to the
previous versions of this IP, but requires the extra bit 31 to be set in
the enable register to actually report the NMI.

Add a mask to allow such an enable bit to be specified, and add this to
the per-SoC data structure. As this struct was just for different register
offsets so far, it was consequently named "reg_offs", which is now no
longer applicable, so rename this to the more generic "data" on the way,
and move the existing offsets into a struct of its own.

Also add the respective Allwinner A523 compatible string, and set bit 31
in its enable mask, to add support for this SoC.

[ tglx: Mop up some coding style along with it ]

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20250307005712.16828-7-andre.przywara@arm.com