irqchip/armada-370-xp: Do not enable it by default when ARCH_MVEBU is selected

irqchip/armada-370-xp: Do not enable it by default when ARCH_MVEBU is selected

The irq-armada-370-xp driver can only be built for ARM 32 bits. The mvebu
family had grown with a new ARM64 SoC which will also select the
ARCH_MEVBU configuration. Since "ARM: mvebu: use the ARMADA_370_XP_IRQ
option", the ARM32 mvebu SoC directly select this new option. Selecting
it by default when ARCH_MEVBU is selected is no more needed.

This patch removes this dependency, thanks to this, a kernel for ARM64
mvebu SoC can be built without error due this driver.

Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Link: https://lkml.kernel.org/r/1454951660-13289-3-git-send-email-gregory.clement@free-electrons.com
Signed-off-by: Jason Cooper <jason@lakedaemon.net>