The GICv3 support is shared between AArch32 and AArch64. For AArch32,
the new AARCH64_IS_NONSECURE is never defined. Use ARM_MULTILIB_ARCH_V4
instead.
This issue was introduced by 76c6caad52.
There is still a change in bsp_interrupt_vector_enable() for AArch32
compared to the version before 76c6caad52.