KVM: arm/arm64: Move cntvoff to each timer context

Make cntvoff per each timer context. This is helpful to abstract kvm
timer functions to work with timer context without considering timer
types (e.g. physical timer or virtual timer).

This also would pave the way for ever doing adjustments of the cntvoff
on a per-CPU basis if that should ever make sense.

Signed-off-by: Jintack Lim <jintack@cs.columbia.edu>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

arch/arm/include/asm/kvm_host.h

@@ -60,9 +60,6 @@ struct kvm_arch {
 	/* The last vcpu id that ran on each physical CPU */
 	int __percpu *last_vcpu_ran;
 
-	/* Timer */
-	struct arch_timer_kvm	timer;
-
 	/*
 	 * Anything that is not used directly from assembly code goes
 	 * here.