irqchip/armada-370-xp: Change register constants prefix to MPIC_

irqchip/armada-370-xp: Change register constants prefix to MPIC_

Change the long ARMADA_370_XP_ prefix in register constants (ARMADA_375_
in one case) to MPIC_. The rationale is that it is shorter and more
generic (this controller is called MPIC and is also used on Armada 38x
and 39x).

Signed-off-by: Marek Behún <kabel@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://lore.kernel.org/all/20240708151801.11592-7-kabel@kernel.org