KVM: arm64: nv: Use reg_to_encoding() to get sysreg ID

Avoid open-coding and just use the helper to encode the ID from the
sysreg table entry.

No functional change intended.

Acked-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230211190742.49843-1-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>

Author: oupton

arch/arm64/kvm/nested.c

@@ -26,8 +26,7 @@
 void access_nested_id_reg(struct kvm_vcpu *v, struct sys_reg_params *p,
 			  const struct sys_reg_desc *r)
 {
-	u32 id = sys_reg((u32)r->Op0, (u32)r->Op1,
-			 (u32)r->CRn, (u32)r->CRm, (u32)r->Op2);
+	u32 id = reg_to_encoding(r);
 	u64 val, tmp;
 
 	val = p->regval;