KVM: selftests: arm64: Rename helper in set_id_regs to imply VM scope

Prepare for a later change that'll cram in per-vCPU feature ID test
cases by renaming the current test case.
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20240502233529.1958459-5-oliver.upton@linux.devSigned-off-by: Marc Zyngier <maz@kernel.org>

tools/testing/selftests/kvm/aarch64/set_id_regs.c

@@ -374,7 +374,7 @@ static void test_reg_set_fail(struct kvm_vcpu *vcpu, uint64_t reg,
 	TEST_ASSERT_EQ(val, old_val);
 }
 
-static void test_user_set_reg(struct kvm_vcpu *vcpu, bool aarch64_only)
+static void test_vm_ftr_id_regs(struct kvm_vcpu *vcpu, bool aarch64_only)
 {
 	uint64_t masks[KVM_ARM_FEATURE_ID_RANGE_SIZE];
 	struct reg_mask_range range = {
@@ -476,7 +476,7 @@ int main(void)
 
 	ksft_set_plan(ftr_cnt);
 
-	test_user_set_reg(vcpu, aarch64_only);
+	test_vm_ftr_id_regs(vcpu, aarch64_only);
 	test_guest_reg_read(vcpu);
 
 	kvm_vm_free(vm);