irqchip/sg2042-msi: Rename functions and data structures to be SG2042 agnostic

irqchip/sg2042-msi: Rename functions and data structures to be SG2042 agnostic

As the driver logic can be used in both SG2042 and SG2044 SoCs, rename
functions and data structures, which are not SG2042 specific, to SG204x*.

Signed-off-by: Inochi Amaoto <inochiama@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Chen Wang <wangchen20@iscas.ac.cn> # SG2042
Reviewed-by: Chen Wang <unicorn_wang@outlook.com>
Link: https://lore.kernel.org/all/20250413224922.69719-3-inochiama@gmail.com