[CORE] Rename arch specific spinlock_t to arch_spinlock_t

The arch provides spinlock_t and core code defines vmm_spinlock_t.

To provide linux compatible spinlock_t in drivers/include/linux/spinlock.t
we rename spinlock_t to vmm_spinlock_t which comflicts with original
arch specific spinlock_t.

This patch fixes spinlock_t conflict by naming arch specific lock as
arch_spinlock_t

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