[DRIVERS] irqchip: Make other drivers and arch/arm independent of GIC APIs

Currently, many parts of arch/arm and local timer driver directly
call gic_enable_ppi() and gic_raise_softirq() for SMP host.

Recent enhancements in vmm_host_irq enables us remove this dependency
on GIC APIs.

This patch makes local timer driver and arch/arm code totally independent
of GIC APIs.

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