KVM: ARM: Reintroduce trace_kvm_hvc

This one got lost in the move to handle_exit, so let's reintroduce it
using an accessor to the immediate value field like the other ones.

Signed-off-by: Christoffer Dall <cdall@cs.columbia.edu>
diff --git a/arch/arm/include/asm/kvm_emulate.h b/arch/arm/include/asm/kvm_emulate.h
index e14268c..9cb2fe1 100644
--- a/arch/arm/include/asm/kvm_emulate.h
+++ b/arch/arm/include/asm/kvm_emulate.h
@@ -158,4 +158,9 @@
 	return kvm_vcpu_get_hsr(vcpu) & HSR_FSC_TYPE;
 }
 
+static inline u32 kvm_vcpu_hvc_get_imm(struct kvm_vcpu *vcpu)
+{
+	return kvm_vcpu_get_hsr(vcpu) & HSR_HVC_IMM_MASK;
+}
+
 #endif /* __ARM_KVM_EMULATE_H__ */