irqchip: mips-gic: Setup EIC mode on each CPU if it's in use

When EIC mode is in use (cpu_has_veic is true) enable it on each CPU
during GIC initialisation. Otherwise there may be a mismatch between the
hardware default interrupt model & that expected by the kernel.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Reviewed-by: Matt Redfearn <matt.redfearn@imgtec.com>
Tested-by: Matt Redfearn <matt.redfearn@imgtec.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/13274/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>