[ARM] arm32: Move i-cache invalidate to cpu_vcpu_cp15_switch_context() from cpu_vcpu_cp15_init().

This patch moves the i-cache invalidate upon vcpu reset to context switching.

This is intended to make i-cache invalidate SMP safe because for SMP systems a vcpu can be scheduled on any host cpu so i-cache invalidate should be done on host cpu when vcpu is scheduled.

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