dsa: mt7530: Utilize REGMAP_IRQ for interrupt handling

Replace the custom IRQ chip handler and mask/unmask functions with
REGMAP_IRQ. This significantly simplifies the code and allows for the
removal of almost all interrupt-related functions from mt7530.c.

Tested on MT7988A built-in switch (MMIO) as well as MT7531AE IC (MDIO).

Signed-off-by: Daniel Golle <daniel@makrotopia.org>
Acked-by: Chester A. Unal <chester.a.unal@arinc9.com>
Link: https://patch.msgid.link/221013c3530b61504599e285c341a993f6188f00.1740792674.git.daniel@makrotopia.org


Signed-off-by: Jakub Kicinski <kuba@kernel.org>