### Summary

When running `ansible -m setup host`, reported `ansible_memtotal_mb` fact changes between invocations.
That's because `setup` reads available non-kernel memory, which fluctuates:

https://github.com/ansible/ansible/blob/2797dc644aa8c809444ccac64cad63e0d9a3f9fe/lib/ansible/module_utils/facts/hardware/openbsd.py#L96-L97

To read total available memory, `hw.physmem` key should be used. Refer to the https://man.openbsd.org/sysctl.2 man, `HW_USERMEM` and `HW_PHYSMEM`.

### Issue Type

Bug Report

### Component Name

setup

### Ansible Version

```console
All.

https://github.com/ansible/ansible/blob/devel/lib/ansible/module_utils/facts/hardware/openbsd.py#L97
```


### Configuration

```console
N/A
```


### OS / Environment

OpenBSD 7.0

### Steps to Reproduce

On OpenBSD host, run this few times:

```
ansible -m setup openbsd_host | grep memtotal
```

Total memory value will be fluctuation between calls.

### Expected Results

I expect to see total installed memory.

### Actual Results

```console
N/A
```


### Code of Conduct

- [X] I agree to follow the Ansible Code of Conduct
device_facts = {}
        devices = []
        devices.extend(self.sysctl['hw.disknames'].split(','))
        device_facts['devices'] = devices
        return device_facts
    def get_dmi_facts(self):
        dmi_facts = {}
        
        
        
        
        
        
        sysctl_to_dmi = {
            'hw.product': 'product_name',
            'hw.version': 'product_version',
            'hw.uuid': 'product_uuid',
            'hw.serialno': 'product_serial',
            'hw.vendor': 'system_vendor',
        }
        for mib in sysctl_to_dmi:
            if mib in self.sysctl:
                dmi_facts[sysctl_to_dmi[mib]] = self.sysctl[mib]
        return dmi_facts
class OpenBSDHardwareCollector(HardwareCollector):
    _fact_class = OpenBSDHardware
    _platform = 'OpenBSD'