[ARM] Make arm32ve arch_vcpu_init() inline with arm64

The virtualization extensions supported by arm32ve and arm64 are
very similar hence, the flow and organization of arch_vcpu_init()
can be similar too.

This patch cleans-up arch_vcpu_init() for arm32ve and makes it
similar to that in arm64.

Signed-off-by: Anup Patel <anup@brainfault.org>