KVM: Clean up kvm_vm_ioctl_create_vcpu()

Since c9d6015 ("KVM: allow KVM_BUG/KVM_BUG_ON to handle 64-bit cond")
'cond' is internally converted to boolean, so caller's explicit conversion
from void* is unnecessary.

Remove the double bang.

Signed-off-by: Michal Luczaj <mhal@rbox.co>
Reviewed-by: Yuan Yao <yuan.yao@intel.com>
base-commit: 76a17bf03a268bc342e08c05d8ddbe607d294eb4
Link: https://lore.kernel.org/r/20230605114852.288964-1-mhal@rbox.co
Signed-off-by: Sean Christopherson <seanjc@google.com>

Author: mmhal

virt/kvm/kvm_main.c

@@ -3975,7 +3975,7 @@ static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, u32 id)
 	if (r < 0)
 		goto kvm_put_xa_release;
 
-	if (KVM_BUG_ON(!!xa_store(&kvm->vcpu_array, vcpu->vcpu_idx, vcpu, 0), kvm)) {
+	if (KVM_BUG_ON(xa_store(&kvm->vcpu_array, vcpu->vcpu_idx, vcpu, 0), kvm)) {
 		r = -EINVAL;
 		goto kvm_put_xa_release;
 	}